Step 1

Preheat the oven to 350°F (177°C). Adjust oven rack to the center rack position. Line the bottom and sides of a 9×13-inch metal or glass baking pan with parchment paper, leaving an overhang on the sides to easily lift the bars out of the pan. Set aside.

Step 2

Whisk the flour, baking soda, ginger, cinnamon, allspice, cloves, nutmeg, pepper, and salt together in a large bowl. Set aside.

Step 3

In a medium bowl, whisk the melted butter, brown sugar, granulated sugar, and molasses together until no lumps remain. Whisk in the egg and vanilla. Pour this into the flour mixture and mix together with a large spoon or silicone spatula. Be sure to mix until no lumps of flour remain. The dough will be very thick and shiny.

Step 4

Transfer dough to the prepared baking pan and press/smooth into an even layer. It may not seem like enough dough, and it will be a thin layer; that’s ok.

Step 5

Bake for 23–26 minutes or until the top is set, but still look quite soft, and a toothpick inserted in the center comes out mostly clean with a few moist (not wet) crumbs. Do not over-bake. Bars puff up in the oven, but settle as they cool.

Step 6

Allow the bars to cool in the pan set on a wire rack for at least 1 hour.

Step 7

In a large bowl using a handheld or stand mixer fitted with a whisk or paddle attachment, beat the cream cheese and butter together on medium speed until smooth and creamy, about 2 minutes. Add confectioners’ sugar, ginger, cinnamon, and allspice, and vanilla extract. Beat on low speed for 30 seconds, then switch to high speed and beat for 2 minutes. Taste. Add a pinch of salt if desired.

Step 8

Spread the frosting on the cooled bars. Top with sprinkles, if desired. To help set the frosting, refrigerate for 30 minutes before slicing and serving. This makes cutting easier and less messy. Use the overhanging parchment to lift the bars out of the pan, and cut into squares.

Step 9

Cover leftover bars tightly and store in the refrigerator for up to 5 days. If you skipped the frosting, cover and store plain gingerbread cookie bars at room temperature for up to 3 days, or in the refrigerator for up to 1 week.