Preheat your oven to 350°F (175°C).
Prepare an 8x8-inch baking pan by greasing it or lining it with parchment paper.
In a medium bowl, whisk together the dry ingredients: flour, cocoa powder, baking powder, baking soda, salt, ground ginger, ground cinnamon, ground nutmeg, and ground cloves.
In a large bowl, mix the wet ingredients: melted butter, brown sugar, granulated sugar, eggs, vanilla extract, and molasses until smooth.
Gradually add the dry ingredients to the wet mixture and stir gently until just combined.
Pour the batter into the prepared baking pan and spread it evenly. Optionally, fold in chocolate chips.
Bake in the preheated oven for 25-30 minutes, until a toothpick inserted comes out with a few moist crumbs.
Let the brownies cool in the pan for 10 minutes, then transfer to a wire rack to cool completely before cutting into squares.