In our final instalment of tasty vegetarian recipes from Chargrilled by Genevieve Taylor we bring you a must-have for any self-respecting BBQ…the burger…the Mexican black bean burger with avocado and chipotle sour cream.

Genevieve says; “Chipotle chilli is one of my favourite spices, providing not only a lovely hit of heat but bags of smoky flavour too. Grilling the squash adds all-important caramelisation and also dries the flesh out a little so your burgers are not too wet and liable to collapse in the pan.” Ready to give it a bash? This recipe serves four.

300g peeled butternut squash, cut into 1cm slices

3 tbsp olive oil

2 tsp cumin seeds

1–2 tsp chilli flakes, ideally chipotle

1 onion, finely chopped

2 garlic cloves, crushed

2 x 400g cans of black beans, drained and rinsed

1 large handful coriander, chopped

2 tbsp plain flour

2 eggs, lightly beaten

125g fresh breadcrumbs

Salt and freshly ground black pepper

A little vegetable oil, for shallow frying

For the chipotle sour cream

3 tbsp sour cream

1 garlic clove, crushed

½ tsp chipotle chilli flakes

To serve

A few lettuce leaves

4 burger buns, lightly toasted

1 large ripe avocado, sliced

1. Preheat a griddle pan on the hob until hot, or use a hot BBQ. Brush the squash slices all over with a tablespoon of olive oil and season with salt and pepper. Lay on the grill and cook on both sides until tender and lightly charred – about 20 minutes. Remove from the heat and chop finely, then put into a bowl and set aside to cool down.

2. Once you are ready to make the burgers, put the cumin seeds and chilli flakes into a dry frying pan and set over a medium heat to toast for a minute or so. As soon as you smell their aroma, tip them into a pestle and mortar and roughly grind.

3. Pour the remaining olive oil into the frying pan, set over a low heat and add the onion and season generously with salt and pepper. Cook for a good 15–20 minutes, until soft and lightly caramelised.

4. Add the garlic and stir-fry for another minute, then tip in the black beans and spices and use a potato masher to break the beans up to a coarse purée. Stir through the coriander and chilled squash, set aside to cool, then chill for an hour to firm up.

5. While the bean mix is chilling, make the dressing by stirring together the sour cream with the garlic and chipotle chilli in a small bowl. Set aside.

6. Put the flour, eggs and breadcrumbs into three separate bowls, ready to coat the burgers.

7. Shape the chilled bean mix into four even-sized balls, then flatten each one to a disc about 1.5cm thick. Take one burger and dip it in the flour to coat evenly all over. Then dip into the egg, followed by the breadcrumbs, carefully turning the burger over to get an even coating. Set on a plate and repeat with the others.

8. Pour a thin layer of vegetable oil into a large frying pan and set over a high heat. Once the oil is really hot, add the burgers. Cook for a few minutes on each side, until they are deep golden brown and crisp. Use a spatula to splash a little oil up the sides of the burgers as they are cooking, to help crisp up the edges.

9. To serve, place a little lettuce and a burger on the base of each bun and top with a few slices of avocado. Add a good dollop of chipotle sour cream dressing, top with the bun lid and tuck in.

Your Guide to Creating the Ultimate Veggie Burger