📖 Instructions

1. Preheat your oven to 375°F (190°C). This is crucial for getting that perfect bake—trust me, I've learned the hard way!
2. Grease a 12-cup muffin tin with butter or cooking spray, or line with paper liners. This prevents sticking and makes cleanup a breeze!
3. In a large bowl, cream together 1/2 cup (1 stick) of softened butter and 3/4 cup of granulated sugar until light and fluffy. This is where the magic starts, folks!
4. Beat in 2 large eggs one at a time, then stir in 1 teaspoon of vanilla extract. Don't forget the vanilla—it makes all the difference!
5. In a separate bowl, whisk together 1 1/2 cups of all-purpose flour, 1 teaspoon of baking powder, 1/2 teaspoon of baking soda, and 1/4 teaspoon of salt. Make sure everything is well combined—no lumps allowed!
6. Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Don't overmix; a few lumps are okay—I promise, it's not going to make a big deal.
7. Peel and dice 2 medium apples into small pieces. Gently fold the apples into the batter. It's tempting to just toss them in, but a gentle fold keeps those apple pieces whole.
8. For the crumble topping, in a small bowl, combine 1/2 cup of all-purpose flour, 1/4 cup of brown sugar, 1/4 cup of rolled oats, and 1/4 cup (1/2 stick) of cold, cubed butter. Use a pastry blender or your fingers to cut the butter into the dry ingredients until the mixture resembles coarse crumbs. If you don't have a pastry blender, fingers work just fine.
9. Fill each muffin cup about 2/3 full with the batter. Sprinkle the crumble topping evenly over the batter. Don't be shy with the crumble; it's the best part!
10. Bake for 20-25 minutes, or until a wooden skewer inserted into the center comes out clean. Keep an eye on them after 20 minutes; ovens vary a bit.
11. Let the muffins cool in the tin for a few minutes before transferring them to a wire rack to cool completely. Impatience is the enemy of a perfect muffin; let them cool down properly!