Prepare Cinnamon Butter; chill.
Grease a 9-inch pie plate. In mixing bowl, combine brown sugar, flour, baking powder, salt and cinnamon.
Add eggs and vanilla; stir till well mixed. Add apples and nuts; stir until well combined. Spoon into pie plate.
Bake in a 350 degree F oven for 30 to 35 minutes or until browned and top feels firm. Serve warm with Cinnamon Butter on top.
In small mixing bowl, beat butter with electric mixer for 30 seconds. Add sifted powdered sugar, ground cinnamon, milk and vanilla. Beat till combined. Cover; chill till firm. Makes 1/2 cup.