The quality of a chocolate cake relies on the quality of the chocolate.

For the best results, buy good-quality chocolate with at least 65% cocoa. It's not sweet but when combined with the sugar its full flavour floods the cake.

Two things separate this cake from the crowd. First, there's no flour so it's suitable for those on a gluten-free diet; and second, the lime zest. Besides flavour, it adds to the aroma when the cake is baking. The result is a rich cake you need only a small slice of, perhaps served with a little creme fraiche.

Dark chocolate cake with lime

Serves 6-8

200g good-quality dark chocolate (minimum 65% cocoa)

180g soft unsalted butter

125g caster sugar

Zest of 5 limes, finely grated

220g ground almonds

4 large eggs, separated

Icing

120g dark chocolate

30g unsalted butter

2tbsp lime curd or lime marmalade

1 lime

Set the oven to 160C/gas mark 2.5. Break the chocolate into small pieces then place them in a heatproof bowl. Set the bowl over a pan of simmering water and leave the chocolate to melt.

Place the butter, sugar and lime zest in the bowl of an electric mixer and beat together until light and creamy. Mix in the ground almonds, egg yolks and melted chocolate, making sure everything is well combined.

Whisk the egg whites until they become stiff then use a plastic spatula to fold the egg whites into the chocolate mixture, again making sure everything is well combined.

Lightly oil a 25cm loose-bottomed round cake tin. Pour the chocolate mixture into the tin, place it in the centre of the oven and bake for 30-35 minutes.

Icing and serving

Once cooked, remove the cake from the tin and place it on a wire rack to cool.

Place the chocolate, lime curd or lime and butter in a saucepan and melt over a very low heat while stirring continuously. When the cake has cooled, spoon the icing over the top and spread it with a palette knife until smooth. Finish by grating lime zest over the top.

The chief flavour in this rich Italian liqueur is of hazelnuts, augmented by hints of vanilla and dark chocolate.

Frangelico, Italy (Wood-Winters, £23)

The Honours, 58a North Castle Street, Edinburgh. Visit thehonours.co.uk or call 0131 220 2513.