Weigh the flours or spoon into a measuring cup and level with a knife. Combine the flours, cinnamon, baking powder, baking soda and salt in a large bowl.
In a batter bowl, combine the buttermilk, ½ cup brown sugar, oil, 1 tablespoon melted butter and egg.
Pour wet ingredients into bowl with flour mixture and stir just until combined. Fold in diced apple.
Place cup cake liners in muffin tin and spoon batter evenly into the twelve cups. Top evenly with streusel. Bake at 400 for 16 minutes or until a toothpick inserted in center comes out clean.
Remove from oven. Cool in pan for 5 minutes and then remove from pan and cool completely.
Mix maple glaze ingredients in small bowl. Drizzle over muffins.
Notes
You could also add dried cranberries or raisins to these!