Preheat oven to 400°F and line a muffin pan with papers or grease with nonstick spray.
In a medium bowl, mix together flours, baking powder, salt, and cinnamon.
In a large bowl, cream together butter and sugar until light and fluffy, then beat in egg and vanilla.
Stir in the flour mixture until just incorporated, then carefully mix in the milk. Do not overmix.
Fold in the apples and 3/4 cup caramel bits.
Divided batter among muffin cups.
To make the topping, in a small bowl or in a food processor, mix together flour, sugars, and butter until crumbly. Divide crumble among muffins (you might have extra crumble).
Bake muffins for 18-20 minutes, until golden brown.
Melt remaining caramel bits in the microwave using 30-second intervals, then drizzle over the tops of the baked muffins.