In a large bowl or bowl of a stand mixer, add the butter and sugar and beat until smooth with hand beaters or your paddle attachment.150 grams granulated sugar, 110 grams brown sugar, 113 grams butter

Add in the wet ingredients and whisk or stir to combine until incorporated.60 grams milk, 160 grams sour cream, 60 grams sourdough discard, 5 grams vanilla, 2 eggs

Fold in the dry ingredients. Mix until the flour mixture is just combined. It’s okay if that batter is a little lumpy, you do not want to overmix.245 grams all-purpose flour, 10 grams baking powder, 3 grams salt, 4 grams cinnamon

Peel and dice the apples (about 2 medium-sized apples). If you want bigger chunks of apples you can dice your apples larger, or if you prefer a softer, more uniform texture, chop them smaller so they melt right into the batter as they bake. Add the diced apples to the batter and fold to combine.200 grams apples

Grease your muffin pan or line it with paper liners. Scoop about ¹/₃ cup of the muffin batter into each muffin liner or muffin tin.

For the streusel, combine flour, cinnamon, and sugar in a bowl. Cut the cold butter into the mixture using your fingers or a pastry cutter until it forms coarse crumbs. Add about 1 tablespoon of streusel to each muffin, making sure it covers the top.45 grams flour, 65 grams sugar, 1 teaspoon cinnamon, 28 grams butter

Bake for 17–20 minutes in a 400°F oven or until a toothpick inserted into the center of a muffin comes out clean or with just a few crumbs.

Cool in the pan for a few minutes, then transfer muffins to a wire rack to cool completely. Add a drizzle of caramel topping right before serving!