Step 1: Preheat Your Oven

1. Preheat your oven to 350°F (175°C).
2. Line a cupcake tin with liners.

Step 2: Make the Cupcake Batter

1. In a large bowl, cream the softened butter and brown sugar until light and fluffy.
2. Add eggs one at a time, beating well after each addition.
3. Stir in buttermilk and vanilla extract until combined.
4. In a separate bowl, mix flour, baking powder, baking soda, and salt.
5. Gradually add dry ingredients to the wet mixture, stirring until just combined.
6. Gently fold in the Biscoff spread.

Step 3: Fill and Bake

1. Spoon batter into cupcake liners, filling each about two-thirds full.
2. Bake for 18-20 minutes or until a toothpick inserted into the center comes out clean.
3. Let cupcakes cool in the pan for 5 minutes, then transfer to a wire rack to cool completely.

Step 4: Make the Biscoff Buttercream

1. Beat the softened butter until creamy and smooth.
2. Gradually add powdered sugar, mixing on low speed to combine.
3. Mix in Biscoff spread and vanilla extract.
4. Add heavy cream one tablespoon at a time until the frosting reaches your desired consistency.

Step 5: Decorate and Garnish

1. Frost cooled cupcakes using a piping bag or spatula.
2. Garnish with Biscoff cookies and drizzle melted Biscoff spread if desired.