Preheat the oven to 375°F. Grease a 10-inch cast iron skillet with butter and set it in the oven on the lower middle rack.
In a large bowl, whisk together the dry ingredients.
In a separate bowl, combine pumpkin puree, eggs, milk, maple syrup, and vanilla. Whisk to combine well. The mixture should be smooth and thick.
Using a rubber spatula, combine the dry ingredients with the wet ingredients. gently fold the pumpkin mixture with the cornmeal mixture just until no dry streaks of flour remain. Do not over-mix.
Place preheated/greased skillet on a heat-safe surface. Scrape batter into skillet, evening out the top into the edges.
Bake for 25-30 minutes or until the top is puffy and golden brown. There should be cracks visible around the edges of the cornbread.
Let the cornbread cool for 5-10 minutes in the cast iron. Then, slice and serve with butter. Enjoy!