Prep the oven and pan: Preheat to 400°F (200°C). Line a 12-cup muffin tin with paper liners or lightly grease with oil or nonstick spray.

Prepare the apples: Peel if you like (optional) and core. Dice into small, even pieces—about 1/4-inch cubes. If prepping ahead, toss with a teaspoon of lemon juice to prevent browning.

Mix the dry ingredients: In a large bowl, whisk together 2 cups all-purpose flour, 1/2 cup granulated sugar, 1/3 cup light brown sugar, 2 teaspoons baking powder, 1/2 teaspoon baking soda, 1/2 teaspoon fine salt, 2 teaspoons ground cinnamon, and a pinch (1/8 teaspoon) nutmeg if using.

Whisk the wet ingredients: In a separate bowl or large measuring cup, whisk 2 large eggs, 1/2 cup neutral oil, 3/4 cup milk, and 2 teaspoons vanilla extract until smooth.

Combine gently: Pour the wet ingredients into the dry bowl. Stir with a spatula until just combined—no dry pockets, but a few small lumps are fine. Do not overmix.

Fold in apples: Add 1 1/2 to 2 cups diced apples and fold gently until evenly distributed. The batter will be thick.

Portion the batter: Divide evenly among the muffin cups, filling them almost to the top for a tall bakery-style dome. Sprinkle the tops with a little turbinado sugar for crunch if you like.

Bake hot, then finish: Bake at 400°F for 5 minutes, then without opening the oven, reduce heat to 350°F (175°C) and continue baking 13–16 more minutes. Muffins are done when a toothpick comes out with moist crumbs, not wet batter.

Cool: Let muffins cool in the pan for 5 minutes, then move to a wire rack. Enjoy warm or at room temperature.