Preheat oven to 350°F (175°C). Grease a donut pan with nonstick spray.
Mix dry ingredients: In a large bowl, whisk together the flour, brown sugar, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, and cloves.
Mix wet ingredients: In another bowl, whisk together the milk, molasses, melted butter, egg, and vanilla extract until smooth.
Combine: Gradually add the wet ingredients to the dry ingredients, stirring until just combined.
Fill the donut pan: Spoon or pipe the batter into the prepared donut pan, filling each cavity about 3/4 full.
Bake: Bake for 10-12 minutes, or until a toothpick inserted into the center comes out clean.
Cool: Allow the donuts to cool in the pan for 5 minutes, then transfer them to a wire rack to cool completely.
Prepare the glaze (if using): Whisk together powdered sugar, milk, and vanilla extract until smooth. Dip each donut into the glaze and let excess drip off.
Serve and enjoy!