Tender, fluffy muffins studded with juicy apple pieces and warmly spiced with cinnamon, crowned with a delicate cinnamon-sugar crust for a cozy, autumnal bite.
Preheat the oven to 375°F (190°C). Grease a muffin tin or line with muffin cups.
Chop the apples into small, even pieces. In a small bowl, mix the topping sugar and cinnamon; set aside.
In a large bowl, combine flour, granulated sugar, brown sugar, cinnamon, baking powder, and salt.
In a separate bowl, whisk together the eggs, milk, oil, and vanilla extract until smooth.
Pour the wet ingredients into the dry and mix just until combined; do not overmix. Fold in the chopped apples.
Divide the batter among the muffin cups, filling each about 3/4 full. Sprinkle tops with the cinnamon-sugar topping.
Bake for 22–25 minutes, or until golden and a toothpick inserted in the center comes out clean.
Cool in the pan for 5 minutes, then transfer muffins to a wire rack to cool. Serve warm or at room temperature.