Preheat your oven to 425°F (220°C) and warm a cast iron skillet inside for about 10 minutes.

Whisk together flour, baking soda, baking powder, salt, and sugar in a mixing bowl until light and airy.

Cut cold unsalted butter into small pieces and work it into the flour mixture until it resembles coarse crumbs.

In another bowl, whisk together pumpkin puree and buttermilk until smooth and creamy.

Create a well in the flour mixture and pour in the pumpkin buttermilk mixture. Fold gently until just combined.

Remove the hot skillet from the oven, add unsalted butter, and allow it to melt. Scoop portions of dough and drop into skillet.

Bake for 15-17 minutes until the tops turn golden brown and smell heavenly. Let cool slightly before adding brown butter.

In a small saucepan, melt the remaining unsalted butter over medium heat until it turns golden brown and nutty.

Drizzle the warm brown butter over baked biscuits and sprinkle with chopped rosemary. Serve fresh and warm.