Put the peas, shallot, garlic, egg and mint in a food processor, then until you get a coarse mixture. Transfer it to a bowl and add breadcrumbs. Season with salt & pepper and add the chilli flakes if used. Form 4 patties and cool them until you’re ready to fry them.
Heat some oil in a large non-stick frying pan. Cook the patties until golden and crispy, about 4 minutes on each side.
Meanwhile, cut the buns in half and toast them gently.
Assemble the burgers, adding lettuce, cucumber, roasted red pepper, onion, tomato etc slices and condiments of your choice.
Serve warm.