Apple Muffin

Preheat your oven to 375°F (190°C) and line a 12-cup muffin tin with paper liners or grease the cups.
In a medium bowl, whisk together the flour, baking soda, cinnamon, and salt until well combined and set aside.
In a large mixing bowl, use an electric mixer to cream the softened butter, granulated sugar, and brown sugar together on medium speed for 2 to 3 minutes, until the mixture is light and fluffy.
Beat the eggs into the butter mixture one at a time, followed by the vanilla extract, scraping down the sides of the bowl as needed to ensure everything is incorporated.
With the mixer on low speed, alternately add the flour mixture and the buttermilk to the wet ingredients, beginning and ending with the flour, and mixing just until no streaks of flour remain.
Gently fold the chopped apples into the batter with a spatula until they are evenly distributed.
Divide the batter evenly among the 12 prepared 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, then transfer the muffins to a wire rack to cool completely.