For the muffin batter: 

Preheat the oven to 375 F. Line muffin tins with baking cups or grease tins with cooking spray and set aside.

Mix the flour, baking powder, baking soda, cinnamon, salt and allspice together in a medium bowl and set aside. 

In a separate bowl, beat together the butter, sugar and eggs until smooth. Add in sour cream, milk and vanilla bean paste and stir until incorporated. 

Slowly add the flour mixture to the wet mixture and stir until smooth.

Carefully fold chopped apples into the mixture. Fill muffin tins 2/3rd full with batter {I like to use a 3 tablespoon cookie scoop for this}. 

For the crumb topping:

In a small bowl, mix the brown sugar, flour, butter and cinnamon. Cut in butter until mixture forms coarse crumbs. Sprinkle crumb topping mixture over muffin batter.

Bake for 20 minutes until golden brown or a toothpick inserted into the center of a muffin comes out clean. Cool muffin pan on a wire rack. 

For the glaze:

Melt the butter in a small saucepan over low heat.  Stir in the vanilla and powdered sugar until combined and then add the maple syrup and water. Remove from heat. Thin with extra water if desired. Drizzle glaze over top of muffins.

This recipe makes approx. 12 muffins, and these freeze exceptionally well!