Line an 8x8-inch metal baking pan with parchment paper. Spread the cookie butter into a square shape about ½ inch thick, staying within the pan’s dimensions. Freeze until solid (about 45 minutes).

Once the cookie butter is firm, lift it out and set aside. Re-line the pan with parchment, leaving overhang on all four sides. Preheat your oven to 350°F (180°C).

In a large bowl, whisk together the sugar, eggs, egg yolk, and maple (or vanilla) extract until smooth and slightly pale.

In a saucepan or microwave-safe bowl, melt the butter and chocolate chunks together until smooth. Stir in the cocoa powder and let cool for 2 minutes.

Whisk the chocolate mixture into the egg mixture until just combined.

Stir in the flour, cinnamon (or chai spice), and salt until no dry streaks remain.

Spread half the batter into the prepared pan. Carefully place the frozen cookie butter slab on top and peel away the

Sprinkle crushed Biscoff cookies over the surface. Warm the remaining 2 tablespoons of cookie butter in the microwave for 15–20 seconds, then drizzle over the top.

Bake for 30–40 minutes, or until a toothpick inserted in the center comes out with a few moist crumbs. Cool completely in the pan on a wire rack.

Once cool, lift out of the pan and cut into squares. Drizzle with extra cookie butter if you’d like a gooier finish.