1. Preheat the oven to 350°F (175°C). Grease and line two 8-inch round cake pans with parchment paper.

2. In a bowl, whisk together the flour, baking powder, salt, and cinnamon. Set aside.

3. In a large mixing bowl, beat the softened butter, brown sugar, and granulated sugar until light and fluffy.

4. Add the eggs one at a time, beating well after each. Mix in vanilla extract.

5. Add the dry ingredients in three batches, alternating with the milk and sour cream, starting and ending with dry ingredients.

6. Divide the batter evenly into the prepared pans and bake for 28–32 minutes or until a toothpick comes out clean.

7. Cool the cakes in the pans for 10 minutes, then transfer to wire racks to cool completely.

8. To make the buttercream, beat the softened butter with Biscoff spread until creamy. Add powdered sugar gradually, then beat in heavy cream until fluffy.

9. Level the cakes if needed. Spread buttercream between the layers and over the cake.

10. Warm the extra Biscoff spread and drizzle over the frosted cake. Top with crushed Biscoff cookies.