Preheat the grill. Arrange the sliced peppers and mushroom caps on the grill rack and grill them for 4-5 minutes, turning once. Beat the eggs and milk together. Chop the mushroom stalks.
Melt the lower-fat spread in a non-stick saucepan and add the eggs and mushroom stalks, stirring with a wooden spoon to set and scramble the eggs. Add the grilled peppers and cherry tomatoes, and cook for a few more seconds.
Meanwhile, warm the pitta bread in a toaster or under the grill. Warm 4 serving plates and place a mushroom on each one. Share the scrambled egg mixture between them and season with black pepper. Serve with the warm pittas.