Apple strudel muffins

Ingredients for the batter:
2 cups all-purpose flour
1 tsp baking powder
1/2 tsp baking soda
1/2 tsp salt
1/2 cup butter
1 cup sugar
2 eggs
1 1/4 tsp vanilla extract
1 1/2 cups, finely chopped apples

for strudel/ topping
1/3 cup packed brown sugar
1 tbsp all-purpose flour
1/8 tsp ground cinnamon
1/3 cup oats
1 tbs butter

Method
Batter: In a bowl, mix all dry ingredients: flour, baking powder, baking soda and salt.
In a large bowl, beat together butter, sugar and eggs until smooth. Mix in vanilla, stir in apples, and gradually add the flour mixture ( dry ingredients) a little at a time making sure that the batter is lump free.

Strudel:In a small bowl, mix brown sugar, flour,oats and cinnamon. Cut small pieces of butter and add in, blend until mixture is like coarse crumbs. This crumb is used as Sprinkle over tops of muffins in muffin pan, before baking .

Bake:Preheat oven to 375 degrees F (190 degrees C). Line with cupcake liners - in a 12 cup regular muffin pan or 24 mini muffin pan. * I sprayed the muffin pan with cooking spray on top of the liners for clean removal of muffins.* Spoon the mixture into the prepared muffin pan - half full only.
Bake 20 minutes in the preheated oven for 12 muffins, or 7-12 mins for mini muffin pan (until a toothpick inserted in the center of a muffin comes out clean). Allow to sit 5 minutes before removing muffins from pan. Cool on a wire rack.