In a bowl, combine flour, sugar, baking powder, and salt. In another bowl, beat eggs, onion, and margarine until blended; stir into dry ingredients just until moistened. Fold in walnuts.
Fill greased or paper-lined muffin cups 3/4 full. Bake at 400° for 10 to 12 minutes if using mini-muffin cups or 20 to 25 minutes if using regular muffin cups or until muffins test done. Cool for five minutes before removing from pans and placing on a wire rack.
Yield: Three dozen mini-muffins or one dozen regular muffins.