Prepare the skillet topping in a medium-sized bowl by mixing the seasoning, baking powder, salt, and baking soda (if using) together.
Add the sourdough starter to the bowl and mix well.
Add the melted butter to the bowl and mix well.
Add the eggs to the bowl and mix well.
Pour the Skillet Topping over the Skillet Mixture in the pan. Top with grated cheese and transfer to the preheated oven.
Bake for approximately 25 minutes at 400°F until the topping is puffed and the cheese is melted and golden. Serve and enjoy!
Well-wrapped leftovers can be stored in the refrigerator and will stay fresh for 2-3 days. Well-wrapped leftovers may also be frozen and will stay fresh for 2 months.
To reheat leftovers, place on a baking sheet in a preheated 325°F oven for approximately 20 minutes until warmed through.