Add 1 tsp of rapeseed oil to a non-stick frying pan and cook the onions, Tenderstem® and chilli until cooked though. Add the balsamic vinegar to the pan and cook out until the balsamic vinegar is fully absorbed by the vegetables. Take out of the pan and leave to cool.
In a large mixing bowl add the plain flour, baking powder, melted butter and eggs and mix with an electric whisk while slowly pouring in the milk. Once fully combined and looking like a cake mixture, fold in the cheese, cooked vegetables, salt and pepper.
Put your muffin cases into a muffin tray and fill each near the top as they will rise a little.
Put in a preheated oven 180c/gas mark 4 for 20-25 mins.
Nutrition analysis of recipes featured on the Tenderstem® website is calculated by a registered dietitian using McCance and Widdowson's The Composition of Foods, Seventh Edition, but may vary slightly depending on the specific ingredients used. Analyses do not include optional ingredients or suggested accompaniments unless specific amounts are given. If there is a range in the amount of an ingredient, the smaller amount is used. When a recipe lists a choice of ingredients, the first is used.