Preheat your oven to 375°F and line a 12-cup muffin pan with paper liners.

In a large bowl, whisk together your dry ingredients. Combine the flour, granulated sugar, baking powder, cinnamon, and salt.

In a separate medium bowl, whisk the wet ingredients. This includes the egg, milk, melted butter, and vanilla extract. Whisk until everything is smooth and combined.

Gently pour the wet ingredients into the dry ingredients. Stir just until moistened.

Gently fold in your chopped apples.

For the streusel topping - combine the flour, brown sugar, and cinnamon in a small bowl. Now, cut in the cold butter. You can use a pastry blender or your fingertips. Work quickly until the mixture resembles coarse crumbs.

Divide the muffin batter evenly among your 12 muffin cups. Pro tip - use an ice cream scoop to make the muffins more uniformed.

Sprinkle a generous amount of streusel topping over each muffin.

Bake for 18-22 minutes. Use a wooden skewer to check the center to see if they’re done.

Let the muffins cool in the pan for a few minutes. Then, transfer them to a wire rack to cool completely. Enjoy!