Preheat oven to 425 degrees.
To make the crumb topping: in a medium bowl, combine all ingredients except the flour. Mix well, then fold in flour. Crumb topping will be thick and crumbly. Set aside.
We used cupcake liners in our muffin tin, less clean up. Or spray a 12 count muffin pan with non-stick spray. We made 16 muffins with this recipe. So either have a 6 count pan handy or you can always bake in two batches! Set Aside.
To make the muffins we used a Kitchen Aid Blender with the paddle. However, a normal blender I am sure will be fine! Beat the butter and both sugars together until creamy. Add the eggs, yogurt and vanilla extract. Beat on medium for 1 minute. The turn to high speed until mixture is combined. Scrape down sides and bottom, to assure a consistent and uniform texture.
Whisk the flour, baking soda, baking powder, cinnamon and salt together in a separate bowl. Pour mixed dry ingredients into the wet ingredients. Add the milk, chopped apples and mix on low speed until everything is combined.
Spoon batter evenly into each cup or liner. Fill 3/4 full. Sprinkle crumb topping onto the top of each muffin. Use a spoon to slightly press crumbs into batter.
Bake for 5 minutes at 425 degrees. Reduce heat to 350 degrees and bake an additional 13-16 minutes or until a toothpick inserted in the center comes out clean. The total time in the oven should be approximately 19-21 minutes.
To make the glaze, whisk all the ingredients together and drizzle over warm muffins.