Preheat oven to 375°F (190°C) and grease a 12-cup muffin tin or line with paper liners.
In a large mixing bowl, whisk together the flour, granulated sugar, brown sugar, baking powder, baking soda, salt, and cinnamon.
In a medium bowl, whisk the Greek yogurt, eggs, melted butter, and vanilla extract until well combined.
Pour the wet ingredients into the dry ingredients and stir with a spatula until just combined.
Gently fold in the diced apples until evenly distributed throughout the batter.
Divide the batter evenly among the 12 muffin cups, filling each about three-quarters full.
Bake for 18 to 22 minutes, or until a toothpick inserted into the center of a muffin comes out clean.
Allow muffins to cool in the tin for 5 minutes before transferring to a wire rack to cool completely.