Preheat your oven to 425 degrees Fahrenheit and coat a muffin tray generously with cooking spray to ensure easy removal after baking.
In a large glass bowl, combine the molasses and butter, microwaving them together for about one minute until melted. Stir well to combine and set aside to cool slightly.
In a separate large bowl, whisk together the flour, ground ginger, baking soda, ground cinnamon, ground cloves, ground nutmeg, and salt until well combined ensuring an even distribution of spices throughout.
Add brown sugar, sour cream, whole milk, and beaten egg into the cooled molasses mixture; mix until thoroughly combined before gradually adding this wet mixture into the dry ingredients just until combined—be careful not to overmix as it may result in dense muffins.
Divide the batter evenly among the prepared muffin cups filling them right up to the top; sprinkle coarse sugar on top if desired for extra crunch before placing them in the oven for an initial bake at 425 degrees Fahrenheit for five minutes.
After five minutes, reduce your oven temperature to 350 degrees Fahrenheit without opening the door; continue baking for an additional 11-14 minutes or until a toothpick inserted comes out clean allowing them to rise beautifully during this stage while creating that signature dome shape on top.