
With the chewy texture of the best fudgy brownie and all the festive flavors of your favorite gingerbread cookies, these spicy bars make a bold statement for the holidays. Browning the butter gives them a deep, caramelized flavor, which rounds out the warming brown sugar and fragrant spices. The white chocolate drizzle on top is purely for looks, so feel free to leave it out if you’re short on time. These bars taste just as good without it.
Heat oven to 350 degrees. Grease a 9-by-9-inch pan and line with parchment paper.
In a small saucepan, heat the butter over medium until melted and flecked with darker brown bits, 5 to 7 minutes. Pour brown butter into a large bowl and add brown sugar, molasses and grated ginger. Whisk until combined (it won't look smooth) and let cool for a few minutes.
Add eggs and vanilla extract, and whisk until smooth and glossy.
Add the flour, baking powder, ginger, cinnamon, salt, allspice, black pepper and cloves. Whisk well to combine. Stir in nuts, if using.
Pour batter into prepared pan. Bake until the edges are firm but the center is still slightly damp, 18 to 25 minutes (add about 5 to 10 minutes if using a glass or ceramic pan). Do not overbake. Transfer pan to a wire rack to cool. Let blondies cool completely in the pan.
Once blondies are completely cool, use a fork, spoon or filled parchment cone to decorate the top of the blondies with melted white or dark chocolate if you like. Let chocolate set for at least 2 hours before cutting into bars.