-
To make the Biscoff cookie filling: Place all the ingredients in a medium heat-proof bowl. Fill a small saucepan with 1" to 2" of water. Bring the water to a boil on the stovetop.
-
Once the water is boiling, turn off the heat and place the bowl on top of the pot. Allow the steam from the water to gently melt the filling ingredients. Stir with a spatula until the mixture is smooth; set aside to cool and thicken to a scoopable consistency while you make the cookies. If it is warm in your kitchen, cover the filling and transfer it to the refrigerator to firm up.
-
To make the cookies: Preheat the oven to 325°F. Lightly grease two baking sheets, or line them with parchment.
-
Weigh your flour; or measure it by gently spooning it into a cup, then sweeping off any excess.
-
In a medium bowl, whisk together the flour and baking soda. Set aside.
-
In a large mixing bowl or a stand mixer fitted with the flat beater attachment, combine the sugar, oil, salt, and spices until smooth.
-
Add the egg and mix until smooth.
-
Stir in the molasses.
-
Add the dry ingredients to the mixing bowl and stir until well combined.
-
Use a spoon or a teaspoon cookie scoop to portion 1" balls of dough and place onto the prepared baking sheets, leaving about 1 1/2" between them on all sides; they'll spread as they bake.
-
Bake the cookies for 11 to 13 minutes, until they're puffed and their edges are set.
-
Remove the cookies from the oven and allow to cool completely on the pans.
-
To assemble the cookies: Once the cookies have completely cooled and the filling is firm, place a heaping teaspoon of filling (again, a teaspoon cookie scoop works well here) onto the bottom side of one cookie, and top with another cookie, flat-side down. Roll the edges of the sandwich cookie in sugar or sprinkles, if desired.
-
Storage information: Store any leftover sandwiched Biscoff cookies, well wrapped, at room temperature for several days; freeze for longer storage.