Step 1

Preheat oven to 425°F. Grease 12 standard size muffin tins and line with cupcake liners. Set aside.

Step 2

In a small mixing bowl, combine all the ingredients for the streusel, using a fork or a pastry cutter to stir together until the mixture resembles wet sand.

Step 3

In a large mixing bowl combine the melted butter and sugars, beating until combined. Add the eggs in one at a time. Add the Greek yogurt, milk and vanilla extract.

Step 4

Add the flour, baking powder, spices and salt. Mix until it begins to come together (not fully incorporated). Add the apple pieces and use a rubber spatula to fold everything together. Batter will be thick.

Step 5

Scoop batter into prepared muffin tins, filling about 3/4 of the way. You can use a large cookie scoop or a 1/4 cup measure to keep things consistent.

Step 6

Sprinkle the tops of each muffin with about 1 Tablespoon of the streusel mixture, pressing the streusel gently into the batter so it sticks.

Step 7

Bake for 5 minutes at 425°F, then turn oven down to 375°F and bake for an additional 15 minutes, until muffins are golden brown and spring back to the touch.

Step 8

If desired, make the frosting while the muffins bake. Combine all the ingredients for the icing in a bowl and mix together until smooth and creamy.

Step 9

Remove the muffins from the oven and allow to cool completely before drizzling with icing and eating!