Preparation:

Step 1: Preheat your oven to 350°F (175°C) and line a cupcake pan with 12 liners.

Step 2: In a medium bowl, whisk together the flour, baking powder, baking soda, and salt. Set aside.

Step 3: In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar together until light and fluffy, about 2-3 minutes.

Step 4: Add the eggs one at a time, beating well after each addition. Mix in the Biscoff spread and vanilla extract until smooth and fully incorporated.

Step 5: Alternately add the dry ingredients and the milk/sour cream mixture, starting and ending with the dry ingredients. Mix just until combined; do not overmix.

Step 6: Divide the batter evenly among the cupcake liners, filling each about 2/3 full.

Step 7: Bake for 18-22 minutes or until a toothpick inserted into the center comes out clean. Let cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 8: Once cooled, use a small spoon or cupcake corer to remove a small portion from the center of each cupcake. Fill with a spoonful of Biscoff spread.

Step 9: To make the buttercream, beat the softened butter until creamy. Add the Biscoff spread and continue mixing until smooth.

Step 10: Gradually add the powdered sugar, mixing on low speed. Once fully incorporated, add the vanilla extract, heavy cream, and salt. Beat on high for 2-3 minutes until light and fluffy.

Step 11: Pipe the Biscoff buttercream onto the cooled cupcakes using a piping bag fitted with a star tip.

Step 12: Garnish with crushed Biscoff cookies and a whole Biscoff cookie on top.