Press parchment paper into an 8X8 pan. Use your finger to create creases into the parchment paper. Melt the cookie butter for 15 seconds in the microwave. Take out the parchment paper and spread the cookie butter in the square. Freeze for at least 2 hours. Cut the cookie spread into squares for easy removal. Put it back in the freezer while you make the batter.
¾ cup Biscoff cookie spread
Preheat oven to 325°F. Spray an 8X8 pan with baking non-stick spray. Line the bottom and 2 sides with parchment paper and spray again. In a saucepan over medium-low heat. Melt the butter and chopped chocolate. Mix constantly until completely melted. Take off heat and allow to cool.
5 tablespoon Unsalted butter, 4 oz Chopped semi-sweet chocolate
In a mixing bowl, sift the flour, cocoa powder, cornstarch, and salt. Set aside. Using a mixer with a whisk attachment. Mix the sugar, eggs, and egg yolk. Mix on high for 5 minutes to get light and fluffy.
1 ⅓ cup White granulated sugar, 2 Large eggs, ¾ cup All-purpose flour, ¾ cup Dutch process cocoa powder, 1 tablespoon Cornstarch, 1 Egg yolk
Add in the vanilla, oil, and melted chocolate/butter. Mix on low until combined. Take off the mixer. Add in the dry ingredients and fold gently. Mix until smooth. Add in cookie pieces and chocolate chips.
1 teaspoon Pure vanilla extract, 3 ½ tablespoon Oil, ½ teaspoon Salt, ½ cup Biscoff cookie pieces
Spread half of the brownie mixture into pan. Very quickly, peel the cookie butter from the parchment paper and place in the pan. Work quickly because it melts fast. Spread the rest of the batter on top. Top with extra cookies.
½ cup Mini chocolate chips, Biscoff cookies
Bake for 40-50 minutes. The middle will be slightly underdone because it will continue to cook while cooling. Allow it to cool completely before cutting into it and serving.