In a small bowl, mix salt, pepper, garlic powder, and 1/2 teaspoon of fresh thyme. Season the pork chops well on both sides.
Melt 1 tablespoon of butter in a cast Iron skillet with a few drops of oil to prevent the butter from burning.
Sear pork chops for 3-4 minutes on one side (at medium-high heat) undisturbed. Flip and cook again for 3 minutes.
Remove the chops from the pan to a plate. Keep it loosely covered with foil.
In the same skillet melt rest of the butter. Add chopped shallots, garlic, and 1-2 sprigs thyme. Saute for 1 minute until the shallots have softened and the garlic is aromatic.
Add flour and saute for 30 seconds. Stir in the stock, whisk well and let it simmer until the sauce starts to thicken.
Reduce heat. Add sour cream and Worcestershire sauce. Mix until no lumps and the sauce is smooth.
Place the cooked chops back into the skillet along with any juice on the plate. Pour over the sauce on the chops and simmer for 1-2 minutes.