Preheat your oven to 350°F (175°C) and grease a 9x13-inch baking dish.

In a large bowl, whisk together the cake flour, crushed Biscoff cookies, ground cinnamon, baking powder, and kosher salt.

Combine sugar and egg yolks in a stand mixer. Beat on medium speed for 5 minutes until thick and pale. Stir in vanilla extract and cream.

Fold the dry mixture into the wet mixture until just combined.

Beat egg whites with cream of tartar until stiff peaks form, then fold into the batter.

Pour batter into the prepared dish and bake for 15-20 minutes until a toothpick comes out clean.

Whisk together heavy cream, sweetened condensed milk, evaporated milk, and warmed cookie butter in a bowl until smooth.

Poke holes across the top of the warm cake and pour the milk mixture evenly over, allowing to soak in.

Let the cake cool for 30 minutes, then cover and refrigerate for at least 4 hours or overnight.

Whip heavy cream with confectioners' sugar and ground cinnamon until soft peaks form.

Spread whipped cream over the chilled cake and garnish with crushed Biscoff cookies.