In a medium bowl, whisk together 2 tsp. salt, 1 1/2 tsp. paprika, 3/4 tsp. black pepper, 1/2 tsp. garlic powder, and 1/4 tsp. onion powder. Sprinkle the mixture liberally over both sides of each pork chop (3 to 4 pork chops).
Set aside 3 Tbsp. flour from 3/4 cups flour to thicken the gravy. Spread out the remaining flour on a large plate. Coat each side of the pork chop in a light layer of the flour.
Place a deep, 12-inch cast-iron skillet over medium heat. Add 3 Tbsp. vegetable oil. Once the skillet is hot enough, brown the seasoned pork chops on each side until golden, but not cooked all the way through, about 5 minutes per side. Remove the pork chops to a plate.
Add 1 large sliced yellow onion to the skillet. Cook, stirring occasionally, until beginning to caramelize, 10-15 minutes. Stir in 3 cloves peeled and minced garlic and cook until fragrant, 30 seconds to 1 minute.
Push the onion and garlic to the side of the pan. Add 2 Tbsp. butter in the center of the pan. Once it melts, mix in the remaining 3 Tbsp. flour. Continue to stir until the mixture becomes golden.
Slowly pour in 2 cups chicken broth while continuously whisking to remove any lumps, then mix with the onions and garlic and any browned bits that may have stuck to the bottom of the pan.
Bring the broth to a boil, then reduce to medium-low and simmer until it starts to thicken, about 15 minutes.
Reduce heat to low and whisk in 1/4 cup buttermilk and 1/4 cup water. Gently nestle back in the browned pork chops, cover, and continue to simmer over low heat until the pork chops are tender and the thickest part is at least 145˚F, 15-25 minutes. The time may vary based on the size of the pork chop.
Remove the skillet from heat, adjust the seasonings as needed, and serve the pork chops warm with the pork chop gravy and a light sprinkling of fresh parsley.