Before you start mixing, measure out all your ingredients and bring the butter, egg, and eggnog to room temperature—this ensures everything combines smoothly without lumps. In a medium bowl, whisk together the flour, ground ginger, cinnamon, nutmeg, cloves, and salt. Set this dry mixture aside. I like to sift the flour with the spices to ensure the spices are evenly distributed throughout the dough, which gives you consistent flavor in every bite.

In a large mixing bowl, beat the softened butter with the brown sugar and granulated sugar for 1-2 minutes until the mixture is light and creamy. Add the room-temperature egg and molasses, mixing until the wet mixture is smooth and well combined. Now add the dry mixture from Step 1 in three additions, mixing until just combined after each addition. The dough should come together into a cohesive mass—don't overmix or your cookies will be tough. The molasses gives these cookies their deep, rich gingerbread flavor, so make sure it's fully incorporated.

Scoop the dough into 1.5-tablespoon balls and place them on a parchment-lined baking sheet, leaving about 2 inches between each one. Cover the sheet with plastic wrap and refrigerate for at least 2 hours, or preferably overnight. Chilling the dough firms it up so the dough balls hold their shape better when you press the thumbprints and bake them.

Preheat your oven to 350°F and line a fresh baking sheet with parchment paper. Remove the chilled dough balls from the refrigerator and gently roll each one between your palms to smooth out any cracks, then coat each ball lightly with a pinch of granulated sugar for a subtle sparkle. Arrange them on the prepared baking sheet 2 inches apart, then use the back of a spoon to press a clear thumbprint into the center of each dough ball—don't press all the way through to the bottom, just about three-quarters deep.

Bake the cookies for 8-10 minutes until they're set on the edges but still soft in the center. Remove from the oven and while the cookies are still warm, use the back of a spoon to gently reshape each thumbprint, pressing it down again if it's puffed up. Let the cookies cool on the baking sheet for 5 minutes, then transfer them to a wire rack to cool completely. This cooling time is important because it allows the cookies to set up before you fill them, preventing the filling from sliding around.

While the cookies cool, combine the chopped white chocolate and eggnog in a microwave-safe bowl. Heat in the microwave for 1.5 minutes, stirring every 30 seconds, until the chocolate is smooth and melted. Transfer the eggnog white chocolate mixture to a piping bag fitted with a small round tip (or use a squeeze bottle for easier handling). Once the cookies are completely cool, pipe the eggnog white chocolate into each thumbprint, filling it generously but not overflowing. I prefer Borden eggnog because it has a richer, creamier texture that makes the filling extra luxurious.

Let the filled cookies sit at room temperature for 30-60 minutes to allow the white chocolate to set up completely. Once set, lightly sprinkle a tiny pinch of ground cinnamon or nutmeg over each thumbprint for a festive finishing touch and a hint of spiced flavor that ties back to the gingerbread cookie base.