1 Spray a frying pan with oil and cook the mushrooms and garlic for a few minutes, until softened.
2 Put into a food processor or blender with the remaining ingredients, except the salt, pepper and flour and blend until smooth.
3 Season to taste with salt and pepper and shape into 4 burgers. Dust lightly with flour on both sides.
4 Spray a frying pan with oil and cook the burgers for 2-3 minutes on each side until golden.
5 Put the salad leaves and tomatoes on the toasted rolls and put the burgers on top. Add a spoonful of mayonnaise, thyme and onions on top of the burgers.