In a large bowl, mix together the flour, sugar, and baking powder.
Use a wire whisk to mix well.
In another bowl, blend the water, orange peel, extracts, and egg whites.
Pour on top of the dry ingredients.
Stir lightly to moisten.
Do not beat or over-stir.
In a third bowl mix the walnuts and brown sugar.
Spoon the batter into 12 muffin cups that have been coated with non-stick cooking spray.
Top the muffins with the nut mixture.
Bake in a preheated 400°F (200°C) oven for 14-16 minutes or until a tester inserted in the middle comes out clean.
Cool the muffins on a wire rack before serving,