1 Make the caramelised onions by placing the olive oil in a large saucepan on a low heat. Slice the red onion and add to the pan. Cook for about five minutes until soft and translucent, stirring regularly. Add the salt and pepper, sugar and balsamic vinegar and cook for a further four to five minutes until sticky and jammy in texture. Remove from the heat and set the onions aside to cool.

2 Meanwhile, preheat the oven to 190 degrees Celsius (170 degrees, fan) or equivalent. Grease a six-hole muffin tin with a little oil, or if you're using a non-stick tin you can skip this. You can also line the tin with muffin cases.

3 In a large bowl, sift in the flour, crumble in the feta cheese, and grate in the cheddar cheese.

4 On a chopping board, chop the sundried tomatoes and spinach into small chunks, and add to the bowl. Add the basil and dried oregano and mix well to combine.

5 In a jug, whisk the egg with the milk, and add to the bowl with the cooled caramelised onions.

6 Mix everything until well combined. Note that your muffin mix will look quite wet. Divide the mixture between the six muffin cases and bake in the preheated oven for 30 minutes.

7 Once cooked the muffins should be golden on top and a skewer inserted into the centre should come out clean.

8 Remove the muffins from the oven and leave to cool in the tin for five minutes before turning out on to a wire rack to cool completely.

9 These muffins can be frozen for up to two months or stored in an airtight container for up to three days.