In a large bowl cream together sugar with shortening. Beat in egg; blend well. Set aside.
Sift together flour, baking powder, salt and cinnamon. Add milk and flour mixture alternating each mixture; until completely mixed. Fold in chopped apples. Fill greased muffin tins half full, then top with mixture of brown sugar, ground nuts, and cinnamon.
Bake in a 375° F oven for 20 minutes, or until center is set Remove from oven. Let cool on wire racks.Servings: 1 dozen muffins