Measure out ½ tbsp portions of Biscoff spread, placing them on a freezable pan. You should have 18 balls of Biscoff spread. Place in the freezer for 1 hour or until completely frozen.
In a medium bowl, whisk together the flour, cocoa powder, espresso powder, baking soda, and salt. Set aside.
In the bowl of a stand mixer, cream the butter, granulated sugar, and dark brown sugar together on medium speed for 1-2 minutes or until light and fluffy.
Add the eggs one at a time, mixing each one completely before adding the next. Mix in the vanilla extract.
On low speed, add the flour in three additions until just combined. Remove the bowl from the stand mixer and scrape down the sides and bottom with a rubber spatula to ensure everything is thoroughly mixed. Don't overmix.
Use a 2 oz (60 ml) cookie scoop to portion out the dough then flatten into a disc. Remove the Biscoff spread from the freezer and place a ball of spread in the middle of each cookie disc. Wrap the dough around the Biscoff spread and roll into a ball.
Place on a cookie sheet and chill in the fridge for 1 hour. About 20 minutes before taking them out, preheat the oven to 350°F (180°C). Line a large baking sheet with parchment paper.
For rolling, place the 50 g (¼ cup) of sugar in a shallow bowl and roll each chilled cookie in the sugar until completely covered.
Place each cookie 2-3 inches apart on the prepared baking sheet and bake for 12-14 minutes or until the edges have small cracks and the centers are puffy.
Let cool on the baking sheet for 5 minutes before transferring to a wire rack to cool completely.