These cookies. THESE COOKIES! I just can’t even describe how amazingly delicious they are — perfectly puffy, soft, chewy, and oozing with Biscoff Spread. My sister-in-law was completely smitten with them.
I think her exact words were, “Katrina! These cookies are insanely amazing. They are way too good to be true. In fact, they should be illegal.” — Katrina Bahl, The Biscoff Cookie & Spread Cookbook
Preheat oven to 375 degrees F.
Whisk together the flour, baking soda, cinnamon, salt, and cream of tartar. Set aside.
In a large bowl using a handheld mixer or stand mixer fitted with a paddle attachment, cream the butter and sugar until light and fluffy, 2 minutes. Add the egg and vanilla and mix until incorporated. Slowly add the dry ingredients to the wet and mix until just combined.
Using a cookie scoop, place 6 rounded tablespoons on an ungreased cookie sheet lined with parchment paper or a silicone baking mat. Gently press the dough down into discs. Top with approximately 1 teaspoon cookie butter, then another disc of cookie dough. Pinch the seam with your fingers to seal in the Biscoff Spread. Roll in the cinnamon sugar and return to the baking sheet.
Bake for 10 to 12 minutes. Allow the cookies to cool on the baking sheet for 4 minutes and transfer to a wire rack to cool completely. Sprinkle each cookie with more cinnamon sugar if desired.