Sprinkle the yeast and brown sugar over warm water in the bowl of a stand mixer fitted with a dough hook. Let stand 5 to 10 minutes until the yeast softens and begins to form a creamy foam.
Turn mixer to the lowest setting and slowly add 2 cups flour 1/2 cup at a time. Add salt, onion powder and 1/4 cup butter. Integrate the remaining 2 cups flour and knead until dough is smooth and elastic, around 5 to 7 minutes.
Coat a large bowl with 1 tablespoon of olive oil. Shape the dough into a ball and place in the bowl, turning to coat all sides with oil. Cover the bowl with a towel and let rise in a warm area until dough has doubled in size, around 45 minutes. Punch down dough and allow to rest for 20 minutes.
Preheat the oven to 400°F. Grease a 12 inch cast iron skillet, and press half of the pizza dough into the skillet. Save the rest in the fridge for some other time.
Heat the oil in a large skillet on medium heat. Cook the onions and garlic until fragrant. Add in the paprika and flour, and stir. Add in the sour cream, dried parsley, dried oregano and mustard, and cook for around 1-2 minutes.
Spread the sauce over the pizza dough. Sprinkle the cheeses evenly on the pizza, then top with the bacon bits.
Bake in the preheated oven for 35 minutes, or until the crust is golden brown. Remove and let sit for 3 to 5 minutes before slicing.