In a medium bowl, whisk together the flour, baking soda, baking powder, and salt. Set aside.

In the bowl of a stand mixer with the beater blade, combine the butter, brown sugar, and granulated sugar. Mix until combined. Add the Biscoff cookie butter and mix until smooth. Scrape down the sides of the bowl with a spatula.

Add the eggs and vanilla extract and mix until combined.

Add the dry ingredients and mix on low until just combined. Don’t over mix. Stir in the Biscoff cookie pieces and chocolate chips.

Scoop about 2 tablespoons of the cookie dough and gently flatten it in the palm of your hand. Place a marshmallow half into the center of the dough. Use your hands to work the dough around the marshmallow so that the marshmallow is covered. Leave some of marshmallow uncovered on top, but make sure the bottom is covered so the cookies don't stick to the pan. Freeze the cookie dough balls for 45 minutes before baking or chill in the refrigerator for 2 hours (or up to 24 hours) before baking.

When ready to bake, preheat oven to 350 degrees F. Line a large baking sheet with parchment paper and set aside.

Place cookie dough balls on prepared baking sheet, about 2 inches apart. Bake cookies for 10 to 14 minutes or until the edges are slightly golden brown, but centers are still a little soft. Remove from oven and sprinkle each cookie with flaky sea salt. Gently press a few Biscoff cookie pieces and chocolate chips into the tops of each cookie. Let the cookies cool for 5 minutes on the baking sheet. Transfer to a wire cooling rack and cool completely.