Summer is the season for burgers. Whatever your dietary requirements I’m betting this applies to you – whether yours are beef burgers in brioche or vegan burgers in a gluten-free bun – there’s something about the warmer weather that seems to make them a nation-wide craving.

This is a recipe I’ve been working on since last summer. It’s had many stages to its life, which were all nice, but none of them were perfect – until, I’ll be so bold as to say, this one. It’s designed as a treat: to literally be the ultimate veggie burger recipe, hence the longer list of ingredients. You can of course simplify it if you wish, and feel free to fiddle to suit your personal tastes.

Ingredients (makes 6):
– 200g sweet potato, peeled and cubed
– 1 red onion, finely chopped
– 3 cloves garlic, finely chopped
– 1½ tsp cumin seeds
– 5 spring onions, roughly chopped
– 75g breadcrumbs
– 1 x 400g tin kidney beans
– 1 x 400g tin butter beans
– 2 tsp smoked paprika
– pinch of chilli flakes
– handful of fresh parsley, roughly chopped

To serve:
– burger buns
– relish (I used M&S’s ancho chilli)
– wild rocket
– cheddar cheese (or vegan alternative)
– avocado, mashed with salt and lime juice
– red onion rings
– alfafa sprouts or cress

1. Begin by preheating the oven to 220°C. Place the sweet potato and red onion on a baking tray, and drizzle over a little olive oil. Sprinkle with the garlic and cumin seeds and toss to coat. Place in the oven and roast for 20-25 minutes, until the sweet potato is soft. Once cooked, put to one side and allow to cool.

2. In a large mixing bowl, roughly mash together the beans. Stir in the spring onions, breadcrumbs, paprika, chilli and parsley.

3. Use a fork to mash the cooled roasted sweet potato, then stir into the bean mixture. Transfer to the fridge and chill for at least 30 minutes.

4. Divide the mixture into 6, and use your hands to shape into patties. Heat a glug of oil in a frying pan, then fry the burgers two at a time. Cook for a few minutes on each side until golden, then transfer to kitchen towel to drain any excess oil.

5. To serve, halve the burger buns and lightly toast. Spread each halve with relish, then add a handful of rocket to the bottom bun. Meanwhile, pop the cooked burger patty on a baking tray with the cheese on top; place under the grill until the cheese has melted. Place the burger on top of the rocket, then top with the smashed avocado, red onion rings and alfafa sprouts.

To make these vegan, simply miss out the cheddar when assembling, and replace the brioche burger buns with regular ones. To make them gluten-free, use gluten-free breadcrumbs for the burgers and buns when assembling. These burgers freeze brilliantly, so even if you’re cooking for one you should still make the full amount.

Tip: Wetting your hands before shaping the patties will stop the mixture from sticking to them.