First cook the spinach: Heat a spoonful of oil in a pan, add the garlic and stir for a few seconds, then add the paprika or cayenne. Give it a stir then add the spinach, drizzle with some balsamic vinegar, combine, then put a lid on. Gently steam over low heat for about 3-5 minutes, then season with salt & pepper. Set aside (keeping it warm).
Put the jackfruit into a food processor. Add the roasted onion, herbs & spices and whiz for a few seconds. Add half of the spinach (without any cooking jus) and whiz again. Transfer the mixture into a mixing bowl. Add the tomato purée and flax-egg. Season with salt and pepper, then combine. Rest for 10 minutes.
When you're ready to cook, stir in enough chickpea flour to create a sticky, malleable mixture- you might need less than one cup.
Form patties between your palms, then fry them in hot oil until golden on both sides.
Meanwhile, toast the buns and prepare your condiments, fillings and toppings.
Reheat the leftover spinach, if needed.
Serve the patties in the toasted buns with your chosen filling & condiments, topped with the remaining spinach.