Prepare oven and pans. If baking right away, oosition a rack in the center of your oven and preheat oven to 350ºF (177°C). Line baking sheets with parchment paper or silicone baking mats.
Combine dry ingredients. In a medium bowl, whisk together the flour, baking soda, baking powder, cinnamon, nutmeg and salt. Set aside. 2 ½ cups (300 g) all-purpose flour 1 teaspoon baking soda 1 teaspoon baking powder 1 teaspoon fine sea salt 1 teaspoon ground cinnamon ¼ teaspoon ground nutmeg
Combine butter and Biscoff spread. In a microwave safe bowl, melt the butter. Then whisk the Biscoff spread into the hot, melted butter until well combined. ½ cup (1 stick, 113 g) unsalted butter ¾ cup (202 g) biscoff cookie butter cookie spread
Add sugars. With a spatula or wooden spoon stir in the granulated sugar and brown sugar until well combined. ½ cup (100 g) granulated sugar 1 cup (213 g) packed light brown sugar
Add eggs and vanilla. Add the eggs and yolk, one at a time, stirring well after each addition. Add in the vanilla. 2 large eggs 1 large egg yolk 2 teaspoons vanilla extract
Add dry ingredients. Stir in the flour mixture. Fold in the white chocolate chips. For best results, cover the dough in plastic wrap and refrigerate overnight. Let the dough sit at room temperature for several minutes just until it is soft enough to scoop. 2 cups (340 g) white chocolate chips
Scoop cookie dough. Using a small cookie scoop, scoop the cookie dough into 2-tablespoon portions placed onto the prepared baking sheets spaced about 2-inches apart.
Bake and cool cookies. Bake for 10-12 minutes, or until golden brown. Remove from the oven and cool for 5 minutes before removing to wire racks to cool completely. I like to top each cookie with a few additional chocolate chip as soon as they come out of the oven for picture perfect cookies. Cookies can be stored in an airtight container at room temperature for up to 3 days.