Preheat oven or toaster oven to 350° F.
Cut away center ribs from chard. Cut chard into thin ribbons, then chop coarsely. Wash chard in salad spinner or colander. Bring small saucepan of water to a boil, add chard, salt. Boil about 10 minutes, until chard is softened and cooked through. Let drain while you prep other ingredients.
Heat olive oil in heavy frying pan. Sauté onions and red bell peppers over medium heat about 3 minutes; add garlic and sauté 2 minutes more. Add mushrooms and soy sauce and sauté 5-7 minutes, or until mushrooms are softened and liquid is evaporated.
Squeeze water from drained chard and place into large plastic bowl. Add mushroom mixture, grated cheese, bread crumbs, beaten eggs mix together. Spray 9 X 9 inch glass or crockery casserole dish with olive oil or non-stick spray. Pour in egg mixture.
Bake 20-25 minutes, until firmly set but not hard, and slightly browned. Let cool slightly, then cut into squares. Serve hot or at room temperature. This is good served with sour cream.