Preheat your oven to 350°F (175°C) and line an 8×8-inch baking pan with aluminum foil. Spray the foil with nonstick cooking spray.

In a medium bowl, whisk together the melted unsalted butter and dark brown sugar until glossy. Add the egg, yolk, and molasses until smooth.

In another bowl, whisk together the all-purpose flour, ground ginger, ground cinnamon, ground cloves, and salt.

Fold the dry ingredients into the wet mixture until a dough forms. Press evenly into the prepared baking pan.

Bake in the preheated oven for 20–22 minutes until set with tiny cracks on top. Allow to cool completely.

In a bowl, beat the softened cream cheese and unsalted butter until smooth. Gradually add powdered sugar and vanilla until fluffy.

Spread a generous layer of frosting over the cooled bars. Refrigerate for at least 2 hours before slicing.