In a large bowl, combine the flour, sugar, salt, and cinnamon; make a well in the center. Add the egg substitute, milk, and vanilla; whisk until thoroughly combined.
Place margarine in a 13x9" baking dish; place in oven until the margarine is melting and sizzling, about 3 minutes. Add apples and mix gently to coat. Bake until the apples are heated through, about 5 minutes. Pour egg mixture over the apples; sprinkle with brown sugar. Bake until the souffle is puffed and golden and a knife inserted in the center comes out clean, about 35 minutes. Serve at once.