Smoky Black Bean Burger

Dry-roast the beans. Heat the oven to 180°C (160°C fan) and give it 20 minutes to come fully up to heat. Pat the black beans dry and spread them in a single layer on the lined tray, then bake at 180°C (160°C fan) for 15-20 minutes, until the skins start to split and the beans feel dry on the outside but are still soft within. Driving off this moisture is what stops the finished patties turning mushy; don't take them so far that they go hard and crunchy.

Soften the vegetables. Cook the onion and pepper in the olive oil over medium heat for 6-8 minutes until soft, then stir in the garlic, cumin and smoked paprika for 1 minute. Tip onto a plate lined with kitchen paper to soak up excess moisture and leave to cool slightly, so the hot vegetables don't start cooking the egg.

Mix the burger mixture. Mash the roasted beans roughly in a bowl, leaving about a third whole for texture, then mix in the softened vegetables, soy sauce, panko, egg, salt and pepper. The whole beans give bite, while the mash binds everything together.

Shape and chill. With wet hands, shape the mixture into 4 patties about 10cm wide and 2cm thick, then chill for 20 minutes. Chilling firms the patties so they hold together when they hit the hot pan.

Prepare the toppings. Slice the red onion into thin rings and separate them. If you find raw onion too sharp, soak the rings in cold water for 10 minutes, then drain and pat dry. Halve, stone and peel the avocado just before you build the burgers and cut it into thin slices so it doesn't brown.

Make the sriracha mayo. Stir together mayo, sriracha, smoked paprika and lime juice in a small bowl. This spicy, citrusy sauce cuts through the earthiness of the beans.

Fry the patties. Heat 2 tbsp of oil in a non-stick pan over medium heat and cook the patties for 4-5 minutes per side until deep brown and crisp, flipping gently with a fish slice as they're more delicate than beef. If using cheddar, lay a slice on each patty after flipping and cover for 1 minute to melt it. Because the mixture contains egg, cook until the centre reaches 74°C.

Toast the buns. Spread butter on the cut faces of the buns and toast them face down in a frying pan over medium heat for 1-2 minutes until golden; a crisp face stops the soft patty and sauce turning the bun soggy.

Build the burger. Spread the sriracha mayo on the cut faces of the buns. On each bottom bun layer lettuce, then tomato, then a patty, then the red onion rings and the avocado slices, and finish with the top bun. The cool avocado and sharp onion balance the warm, smoky patty.