Coat an 8-inch waffle iron with cooking spray and preheat.
Combine flour and next 3 ingredients in a medium bowl. Combine yogurt, egg substitute, and margarine; add to dry ingredients, beating well with a mixer at medium speed. Stir in pecans.
Pour 1 cup batter onto hot waffle iron, spreading batter to edges. Bake 4 to 5 minutes or until steaming stops. Cut each waffle into 4 squares. Serve with maple syrup, if desired (syrup not included in analysis).
Tip: One of the best ways to bring out the flavor of nuts is to toast them. Just place any kind of whole or chopped nuts in a shallow pan or on a baking sheet, and bake at 350° for 6 to 8 minutes. Be sure to watch them carefully; they can go from toasted to burned very quickly.