Whirl the crackers for a few times in a blender or food processor to make fine crumbs. Mix in the baking powder and set aside. Beat egg whites until stiff, but not dry. Gradually add 1 1/4 cup sugar, a little at a time, beating until stiff. Gently fold in 1 teaspoon vanilla, nuts and crumbs; mix well. Pour into a greased pie plate. Using a spatula, make the edges a little taller than the middle. Bake at 350° for about 30 minutes or until golden brown and firm. Let cool.