Yields 22 - 24 medium muffins
Preheat oven 350 degrees. Spray and coat 24 medium muffin cups with cooking oil.
Place 1 tablespoon of cider vinegar in a 1 cup (or larger) measuring cup. Add enough unsweetened soy milk to measure to the 1 cup line. Let the mixture set for 10 minutes, stir occasionally.
Mix dry ingredients together and add semi-sweet chocolate chips and walnuts. Beat egg whites, add milk, banana, decaf coffee (or Teeccino), and oil.
Add the wet mixture to the dry mixture and mix only enough to dampen all the flour. Spoon the batter into the prepared muffin cups and fill to about 3/4 full.
Bake muffins 15 - 20 minutes. Test for doneness by inserting a knife in the middle of the muffin. If it comes out dry, the muffin is done. These muffins will freeze really well in a plastic freezer bag or container.