The group said revenues increased 4.5% to £139.7 million in the six months to January 11, with underlying profits up 47% to £7.2 million.
Thornton's commercial operation, which includes sales to other retailers such as supermarkets, grew turnover by 14.5% to £70.6 million in the period and now represents the biggest part of the business.
Total sales in the retail division declined 4% to £69.1 million as a result of an ongoing store closure programme which left it with 36 fewer sites than a year earlier. It ended the period with 281 stores as it works towards a profitable estate of between 180 and 200 sites in the medium term.
Excluding changes in store space, retail sales were 2.1% higher than a year earlier after a strong Christmas selling season was boosted by "outstanding" sales from its advent calendars and Snowman ranges.
Chief executive Jonathan Hart said the company looked forward to the key spring seasons of Mother's Day and Easter with confidence.
He added: "Going forward our focus remains firmly on continuing our current strategy and maintaining the positive trajectory that we have established over the past two years.
"As a result of the growing production volumes we are also investing in increasing our manufacturing capacity to support our long-term objectives."