Sauté green onions and 1 clove of minced garlic in 2 Tbsp (30 mL) olive oil for two minutes, until onions are soft. Add cumin and mushrooms; cook for another three minutes, until mushrooms are cooked.
Remove to a medium bowl. To this mixture, add puréed chickpeas, minced parsley, bread crumbs, tahini (if using), two thirds of the mint and 1 Tbsp (15 mL) lemon juice. Stir until combined. Season to taste.
In handfuls of about 1/2 cup (125 mL), shape and flatten mushroom mixture into four patties. Brush both sides with remaining 1 Tbsp olive oil, place on a baking sheet and bake for 15 minutes. Turn over and cook another 15 minutes until cooked through and browned. If you prefer, you can also cook patties on the stovetop.
To make yogurt sauce: Mix together yogurt, remaining one third of mint, 1/2 clove of garlic and 1 Tbsp lemon juice; season with salt and pepper. Place three slices of tomato on each plate, top with a burger, then drizzle with yogurt sauce, and garnish with pickles and remaining parsley.
Per serving: 370 calories, 13 g protein, 14 g fat (2 g saturated fat), 52 g carbohydrates, 10 g fibre, 2 mg cholesterol, 713 mg sodium