Preheat your oven to 350°F (175°C) and grease three 6-inch cake pans, dusting them with flour.

In a bowl, whisk together all-purpose flour, baking powder, and salt, then set it aside.

Cream softened unsalted butter and granulated sugar in a stand mixer until light and fluffy, about 3-4 minutes.

Add eggs one at a time, mixing well after each addition, then stir in the vanilla extract.

Gradually mix in the dry ingredients alternating with milk, beginning and ending with dry.

Divide the batter evenly among the pans, smooth the tops, and bake for 25-30 minutes until a toothpick comes out clean.

Allow to cool for 10 minutes before transferring to a wire rack to cool completely.

In a clean mixing bowl, combine egg whites and granulated sugar, whisking until mixed.

Set the bowl over a pot of simmering water, whisking continuously until the mixture is hot and smooth, reaching 160°F.

Carefully transfer to a stand mixer and whip on medium-high until stiff peaks form and the mixture cools down to room temperature.

Gradually add in cubed room-temperature unsalted butter while mixing on medium speed until smooth and creamy.

Fold in the smooth cookie butter for a delightful flavor.

Begin assembling your Biscoff Cake by placing one layer on a serving plate.

Spread a thin layer of crunchy cookie butter on top.

Frost with approximately 2/3 cup of your prepared Biscoff buttercream.

Repeat this process for the second layer, then add the final layer on top.

Apply a crumb coat to seal in any crumbs and chill the cake in the refrigerator for 20 minutes.

Once chilled, retrieve the cake and finish frosting it with the remaining Biscoff buttercream.

Decorate the top and sides with rosettes made from the buttercream, then sprinkle with crushed Speculoos cookies.

Slice your stunning Biscoff Cake and serve at room temperature or slightly chilled.

Enjoy the joy of sharing this delightful creation, celebrating its rich flavors in every bite!