PREHEAT THE OVEN: Set the oven to 350°F (175°C) and line two baking sheets with parchment paper to prevent sticking and promote even browning.

CREAM THE WET INGREDIENTS: In a large mixing bowl, beat the softened butter, Biscoff spread, and brown sugar using a hand or stand mixer on medium speed until the mixture is smooth, fluffy, and lightened in color, about 2 minutes.

ADD EGG AND VANILLA: Mix in the egg and vanilla extract until fully incorporated and the batter looks creamy and cohesive.

WHISK THE DRY INGREDIENTS: In a separate bowl, combine the all-purpose flour, baking soda, salt, and optional cinnamon. Whisk until evenly blended.

COMBINE DRY WITH WET: With the mixer on low speed, gradually add the dry ingredients to the wet mixture. Mix until a soft, even dough forms, being careful not to overmix.

PORTION THE DOUGH: Use a cookie scoop or spoon to portion about 2 tablespoons of dough per cookie. Place each scoop onto the prepared baking sheets, spacing them 2 inches apart.

BAKE THE COOKIES: Bake for 9 to 11 minutes, or until the edges are set and just beginning to brown while the centers remain slightly underdone. This ensures a soft, chewy texture.

COOL THE COOKIES: Let the cookies rest on the baking sheet for 5 minutes to finish baking from residual heat, then transfer them to a wire rack to cool completely.