Preheat and prep. Heat your oven to 350°F (175°C).
Place a 10-inch cast iron skillet in the oven while it preheats. This helps create a lightly caramelized crust.
Whisk the dry ingredients. In a large bowl, whisk 2 cups flour, 1/2 cup brown sugar, 1 teaspoon baking soda, 1 teaspoon baking powder, 1/2 teaspoon kosher salt, 1 1/2 teaspoons cinnamon, 1 teaspoon ground ginger, 1/4 teaspoon cloves, and a pinch of nutmeg if using. Break up any brown sugar clumps.
Mix the wet ingredients. In a separate bowl or large measuring cup, whisk 3/4 cup buttermilk, 1/2 cup molasses, 1/2 cup neutral oil, 2 large eggs, and 1 teaspoon vanilla until smooth and glossy.
Combine gently. Pour the wet mixture into the dry.
Stir with a spatula just until no dry streaks remain. The batter should be thick and silky. Avoid overmixing to keep the crumb tender.
Butter the hot skillet. Carefully remove the skillet from the oven and add 1 tablespoon unsalted butter, swirling to coat the bottom and halfway up the sides.
The butter should sizzle.
Bake. Scrape the batter into the hot skillet and smooth the top. Bake for 22–28 minutes, until the center springs back and a toothpick comes out with a few moist crumbs. Edges will be set and slightly darker.
Cool slightly. Let the cake rest in the skillet on a rack for 10–15 minutes.
This sets the crumb and makes slicing easier.
Whip the cream. In a chilled bowl, whisk 1 cup heavy cream with 1–2 tablespoons powdered sugar and a pinch of salt until soft peaks form. Don’t overwhip; you want it cloud-like.
Serve. Slice the warm cake and top each piece with a generous spoonful of whipped cream. A sprinkle of cinnamon or a drizzle of warm honey is a nice touch.