Combine diced apple with lemon juice, cinnamon and nutmeg. Reserve.
Combine flour, baking powder, brown and white sugars in a large bowl. Mix well. In a separate bowl beat eggs with milk and melted butter.
Pour wet ingredients over dry ingredients and combine until just blended. Stir in apple mixture.
Spoon muffin mixture into greased muffin pan and bake in a preheated 400-degree oven for 25 minutes.