Preheat your oven to 350°Fahrenheit and prepare two 8-inch round cake pans. Spray them with nonstick cooking spray and then line them with parchment paper rounds.
In a large bowl, whisk together the flour, cocoa powder, sugar, baking powder, baking soda, and salt.
Add the eggs, oil, vanilla extract and milk. Add the hot water and mix until smooth.
Divide the batter evenly between the two prepared cake pans and bake for 20-26 minutes, or until a toothpick inserted in the middle comes out clean.
Let the cakes cool for 20 minutes in the pan, then remove from the cake pans to cool completely on a wire cooling rack.
Once the cakes have cooled you can make the Biscoff buttercream. In the bowl of a stand mixer or in a large bowl with a handheld mixer, beat the butter and Biscoff spread together until smooth.
Add the the salt and the icing sugar a ¼ cup at a time until the frosting is the consistency you would like. If the frosting gets too thick you can add 1 tablespoon of milk at a time. If the frosting is too thin then continue adding ¼ cup of confectioners’ sugar until it is thick.
Frost the cooled cakes with the cookie butter frosting and decorate with Lotus Biscoff cookies!