Step 1
Preheat oven to 375°F. Line one muffin pan with paper liners.
Step 2
Prepare the streusel. In a medium bowl, mix all the ingredients of the streusel until crumbly. Place in the refrigerator while you prepare the muffin batter.
Step 3
In a medium bowl, whisk together the flour, cinnamon, baking powder, baking soda, salt, and nutmeg. Set aside.
Step 4
In a large bowl, cream the butter and sugar until light and fluffy. Scrape the sides of the bowl. Add the eggs, one at a time. Add vanilla and mix until well incorporated. Add the flour mixture and mix until just combined. Scrape the sides of the bowl as needed. Add the sour cream and apples and mix until just combined.
Step 5
Fill the muffin cups with batter and top with streusel. Bake for 20-22 minutes or until golden brown and a toothpick inserted in the middle of the muffin comes out clean. Remove from oven, cool in the pan for 5 minutes. Remove from pan. Enjoy!
To prepare blueberry muffins, you can use the same recipe by removing the cinnamon and nutmeg from the batter and replacing the grated apples with 2 ½ cups of fresh blueberries.