1. Portion & Freeze the Filling:

1. Stir Biscoff spread to loosen it slightly (it should be at room temperature).

2. Dollop 14 mounds (≈2 tsp / 10g each) of Biscoff onto a lined tray.

3. Freeze until firm, approximately 30–45 minutes. These should peel off easily but still spread when baked.

2. Brown the Butter:

1. In a light-colored saucepan, melt butter over medium heat. Continue cooking, stirring constantly until the milk solids turn amber and the butter smells nutty (this takes about 3–5 minutes after melting).

2. Immediately scrape the browned butter into a heatproof bowl, including the browned bits. Allow it to cool for 10–12 minutes until it’s just warm (not hot) so that the sugars don’t melt excessively when mixed.

3. Mix Wet Ingredients:

1. Add the brown sugar, granulated sugar, and 15g of Biscoff to the browned butter. Whisk or beat for 1–2 minutes until the mixture looks like thick, glossy wet sand.

2. Add the whole egg, egg yolk, and vanilla extract. Mix for another 1–2 minutes until the mixture is emulsified and slightly lightened. The dough should start to thicken.

4. Combine the Dry Ingredients:

Whisk the flour, cornstarch, baking soda, baking powder, salt, cinnamon, and nutmeg in a separate bowl.

5. Form the Dough:

1. Fold the dry ingredients into the wet mixture just until a few flour streaks remain.

2. Gently fold in the crushed Biscoff biscuits (and optional chips), being careful not to overmix. Stop once the mixture is uniform.

6. Chill the Dough (Recommended):

Cover the dough and chill for 30–60 minutes. Chilling the dough ensures thicker cookies and makes it easier to stuff. If you chill for more than 2 hours, allow the dough to soften a bit before scooping.

7. Preheat the Oven:

Preheat the oven to 350°F / 175°C (no fan) or 165°C (fan). Line your baking sheet with parchment paper.

8. Stuff the Cookies:

1. Portion the dough into 14 balls, each weighing about 60–62g before adding the filling.

2. For each ball, flatten the dough into a thick disk, place a frozen Biscoff center in the middle, then wrap the edges of the dough around the filling and seal the seams well. Keep the filling centered. Lightly roll the dough back into a ball.

3. Press a few extra crushed biscuits on top of each cookie. Optionally, add a shard of white chocolate for extra richness.

9. Bake the Cookies:

1. Arrange 6–7 stuffed cookie dough balls per sheet, leaving enough space for spreading.

2. Bake for 10–12 minutes until the edges are set and the centers remain puffy and slightly pale. The internal temperature should reach about 185–190°F (85–88°C) if using a thermometer.

3. For a crinkled effect, gently lift the tray and tap it once after 8–9 minutes of baking.

4. After removing the cookies from the oven, immediately use a round cookie cutter (larger than the cookie) to swirl and shape them into perfect circles.

5. While still warm, sprinkle flaky salt and crushed biscuit crumbs for an extra touch of flavor.

10. Cool the Cookies:

Let the cookies rest on the baking tray for 8–10 minutes. This allows the carryover heat to finish cooking the centers while keeping the Biscoff filling molten. Afterward, transfer them to a wire rack to cool completely.