Preheat oven to 400*F. Put an 8 or 10 inch cast iron skillet in the oven to preheat.
Add vinegar to a 1 cup (8 ounce) measuring glass. Pour in milk to make it one cup. Set aside.
Whisk together flour, cornmeal, baking powder, and salt. Set aside.
In another bowl, stir together milk, egg, honey, and pumpkin puree. Pour wet mixture into dry mixture and stir until just combined (don't over mix).
Carefully take the skillet out of the oven, and add in butter. Let melt and swirl butter around pan so it's evenly distributed.
Pour batter into skillet and bake in preheated oven for 18-22 minutes until done. Enjoy!
Notes
*Do not use low fat or fat free milk. Whole milk and 2% are best. I haven't tested it, but unsweetened almond milk or coconut milk could work. *Make sure to use white whole grain flour or whole grain grain pastry flour. Using regular whole wheat flour could make your cornbread too dense.