Roasted until they're crispy or slathered in cream, garlic and butter and then baked in the oven into a dauphinoise?

It is, I think, the ultimate potato dilemma. I've been thinking about it for the last few days, since I found out I would be interviewing TV presenter, writer and self-confessed potato lover Dawn O'Porter. Chips, I assumed, would be too obvious and boiled, well, no one chooses boiled as their favourite do they? I toyed with the idea of throwing in mashed as an option, but dismissed it at the last minute.

Just as well really. O'Porter wouldn't choose mashed, or any of the other potato options I'd thought of for that matter. Instead she would prefer something a little simpler. "Just fry it, just fry the goddamn thing," she says, matter-of-factly. Until they're crispy? With butter or oil, and some seasoning? I don't ask. There would be no point. O'Porter clearly wants to be straightforward about her potatoes - but then that's how she is about most things in life.

Speaking of lives, here's a little bit about O'Porter's: born near Loch Lomond, raised in Guernsey, she rose to fame in the late 2000s with her own chatty, no-nonsense brand of television, presenting documentaries such as Dawn Gets Naked and Super Slim Me. A regular face on BBC3 and Channel 4 for a number of years, she's experimented with lesbianism, helped to deliver a baby and re-enacted the final dance scene from Dirty Dancing all in the name of light entertainment.

In 2012 O'Porter married actor Chris O'Dowd - he of The IT Crowd and Bridesmaids fame - in London. Rather than do the traditional thing and take his name, O'Porter (then Porter) decided just to take O'Dowd's O. It was a move that raised a few eyebrows and, let's be honest, solicited some slightly-sneering comments, but O'Porter has always defended her decision to amalgamate their names. Not long after the wedding she wrote: "I am lucky that I have the option to keep Porter prominent and take a tiny letter that, for me, expresses the unity with my husband that I am proud of."

It would be a mistake to assume that O'Porter could be summed up in a few paragraphs about celebrity marriage and light entertainment TV programmes though. There's more to this 35-year-old than that. In 2009 she made a revealing two-part documentary series on breast cancer for Sky, something she describes as "one of the hardest things I have ever done", particularly because her mother, Carol Rix, died of the disease just before O'Porter's seventh birthday. Last year she edited The Booby Trap, a "big book of all things booby" in aid of breast cancer charities. She has also written two teenage fiction novels and one somewhat revealing book on internet dating. Her new Channel 4 series, This Old Thing, about vintage clothing, will air in May and will also be accompanied by a book.

Whether it's been heart wrenchingly sad or you-didn't-just-say-that shocking, each TV programme and book has been delivered with the same O'Porter trademark of straightforwardness. She's the kind of woman who proudly wears her heart on her sleeve and who always says what she thinks, regardless of what people might think.

"I'm not into this famous people giving PR answers and being really safe," she says. "Chris and I are not afraid of saying stuff that might piss people off if it's what we feel, and I think that's what your duty in the public eye is to do."

Right now what O'Porter feels like is a cup of herbal tea. A friendly chap in the Waterstones cafe in Glasgow brings some over and informs us that O'Porter's dad, Bill, has finally been located on one of the floors upstairs. O'Porter has just finished a book signing for her latest novel Goose and her dad is accompanying her for the day. The book, which is about the loves and lives of two teenage friends Renee and Flo inspired loosely by her own teenage diaries, is a follow-up to O'Porter's debut fiction novel Paper Aeroplanes. The latter title earned her a nomination for best teenage book in the 2014 Waterstones Children's Book Prize awards.

O'Porter tells me the signing went well, though it wasn't particularly busy. She hadn't expected it to be - it's Sunday and it's Mother's Day - but she's pleased because it means she will be able to have a relaxed dinner with her father tonight, before heading to Newcastle to continue on the book tour.

"My dad lives up on Loch Lomond," says O'Porter, who moved to Guernsey with her mother and sister at the age of one. "I would spend the school holidays [there] - it's beautiful up there, I love it."

Loch Lomond might be beautiful, but home (for the next six months at least) is New York. O'Dowd is currently starring in a Broadway adaptation of John Steinbeck's Of Mice And Men, and the couple, along with their cat Lilu and their dog Potato (the name was "a no brainer") have recently relocated to the city from Los Angeles where they have been living for the last six years. I ask O'Porter if she likes living in America. "I love it," she replies instantly. But she's keen to clear something up. O'Porter was there first - living in LA before O'Dowd that is. Apparently everyone assumes she followed him there on his quest for Hollywood stardom. Not true. "I was living there long before I ever met him, and I had a place there and he ended up moving in with me."

In fact O'Porter moved to LA six years ago to film her Channel 4 series on polygamy. O'Dowd moved to America later and the two then met at a party. At the time he had only starred in The IT Crowd, which O'Porter hadn't seen. So, she points out, the notion that she chased her husband halfway around the world is a nonsense. "A lot of people say to me, 'So you went to Hollywood for Chris?' and I say, 'I did not pack my bags and move to the other side of the world for a man'. I was there of my own accord."

Of course nowadays O'Dowd is hot property in Hollywood. The Irish actor starred in Bridesmaids and has appeared in the hit TV American series Girls. O'Porter meanwhile has been pursuing her writing and presenting careers. Does she find it hard to have a celebrity partner? "Not really, because I still write so much. I feel like Chris is the famous one, which is nice, and I still kind of do the same thing. When I walk down the street without Chris I'm not famous, when I walk down the street with Chris I am."

Granted O'Porter might not be as famous as her Hollywood actor husband, but it would be wrong to portray her as some sort of little-known TV presenter. With her trademark brown bob, chunky blunt fringe and penchant for natty vintage clothing O'Porter is arguably one of the most recognisable media personalities in the UK. At times she's also been one of the most talked about.

In the late 2000s the often shock subjects of her TV documentaries (and the things she was willing to do for them) catapulted her to fame. In Super Slim Me O'Porter starved herself to become a size zero and highlight the dangers of extreme dieting, while in The Free Lovers, the Channel 4 documentary about the world of polyamory, O'Porter, together with the members of the 1960s-style Zegg commune in Germany, went into a room, stripped off and got covered in oil.

While the subject of each documentary may have been worthy of discussion, it was O'Porter's actions that generated the most publicity - and divided opinion. I ask O'Porter about that period in her career, when she was in her late 20s. "I feel like I was really frantic: I've got to get this done, that done, career, career, travelling, get everything done. I think I was fiercely ambitious and that was the number one thing."

O'Porter believes her then ambition-fuelled life may have had something to do with her mum. "I think it's losing a parent really early - just two days before I was seven - I have this slight 'we're going to run out of time' [feeling]. I have to fit in as much as possible, which is slowing down the older I get.

"I think it was the feeling of just wanting to feel like, OK, if I die tomorrow I've achieved great things and I absolutely feel like that is [the case] now, but you don't feel like that in your 20s. I think that's all I ever wanted, was to go: I have left a legacy. I feel like I've written books now, so it's fine I can go. I'm so much more relaxed now than I ever was, I imagine I was quite intense to be around when I was in my 20s. I'm kind of mortified by my 20s actually."

Does the relaxed, content 35-year-old O'Porter think she would have liked her "intense" 20-something self? "Probably not," she says candidly. "I think I would have found me really annoying. I think I thought everyone really cared about listening about me, so I would harp on about me, which I find excruciating. I didn't ask people enough questions about them and I would quite happily take the floor if someone would let me and just do a little performance - but I was in my 20s and it's OK to be a dick in your 20s. I just think people would describe me as a bit relentless. A bit exhausting. I feel like I'm definitely different now, I don't feel like people would say that now."

Maybe not. Certainly the O'Porter I meet doesn't appear to be relentlessly career- driven. She seems more relaxed than that, more at ease. Perhaps the change has something to do with being happily married to O'Dowd, maybe it's just an age thing. Whatever the reason I wouldn't describe O'Porter as relentless, or to use her own words, "a dick".

What would I say about her? I admire her courage. Particularly around the subject of breast cancer. Aside from the documentary and the book, O'Porter continuously campaigns to raise awareness and funds for breast cancer charities. It's not something she needs to do - it's not even something, I imagine, that's emotionally comfortable to do - but she does it all the same.

Up-front as ever, O'Porter sees her involvement with breast cancer charities like this: "My mum died 28 years ago. I think it would be selfish of me not to do breast cancer work because it was all too hurtful for me, when I spend so much time with women who are dying and leaving their children behind. I didn't die, my mum died, so it would be ridiculous of me to say that it was too emotional. And who cares even if it did - I bawl my eyes out every time I do anything for breast cancer, but that's all right, it's a sad subject and it's heartbreaking."

It is, but O'Porter talks about it in the same open and frank way she does to me about Botox, bikinis and, well, baring her anatomy (or not) in public. The last topic comes up when I mention her Twitter handle, Hotpatooties. It's named after the Meat Loaf song in The Rocky Horror Picture Show, but O'Porter admits people assume it means something else. "Hotpatooties sounds like 'great tits'," she announces before saying, "I've got great tits … or I used to. God, I haven't even had a child and where have they gone?"

It's an awkward moment; hard to know what to say when someone brings up the appearance of their breasts, albeit in an obviously lighthearted way. I plump for the standard compliment: I'm sure they're fine. She shrugs. "I'd show you but … it's just not the right time. Or place. Although something tells me I've got my tits out in a coffee shop at some point in my life. But you know, not recently." Of course not, O'Porter is too grown up for that now. n

Dawn O'Porter presents This Old Thing on Channel 4 next month. An accompanying book is published by Hot Key Books, priced £20. Goose is published by Hot Key Books, priced £7.99. Visit dawnoporter.co.uk.