Preheat the oven to 425 degrees F and place an 10-12 inch cast iron skillet in the oven.
In one bowl, whisk or sift the dry ingredients.
In another bowl, whisk the wet ingredients together with 1 1/4 cup of the shredded cheddar (reserving 3/4 cup for topping) until combined.
Pour the wet ingredients into the dry ingredients. Fold together with a rubber spatula, until combined and there are no clumps (except for the peppers/cheese/scallions!)
Remove the hot skillet from the oven. Quickly add 2 tbsp of butter to the skillet and let it melt.
Pour the batter into the skillet on top of the melted butter. Top with the remaining 3/4 cup of cheddar and bake for 25-30 minutes, until golden brown.
Remove from the oven. Flip the skillet onto a rack and let the cornbread cool for 15 minutes before serving.