Use a skillet that is large enough to arrange pork chops in a single layer. Heat large skillet over medium high heat. Add 2 tablespoons olive oil to coat bottom of hot skillet.
Use paper towel to pat pork chops dry, season with salt and pepper, and arrange in hot skillet in single layer. Cook until brown on first side, flip and brown on second side. Remove pork chops to a plate.
Add remaining tablespoon of oil to skillet, add onions and mushrooms. As liquid is released, use spatula to loosen browned bits from bottom of pan. Stir occasionally until onions & mushrooms are soft. Sprinkle flour, garlic, and oregano over onion/mushroom mixture, stir and continue to cook for 1 minute. Stir in chicken broth, thyme, and bay leaf. Add browned pork chops back in along with any drippings. Bring to boil, reduce heat to low, and simmer 30-40 minute until pork is tender (a paring knife can be easily inserted with little resistence).
Remove pork chops to platter and cover with foil. If sauce in skillet is too thin, increase heat to medium-high and cook uncovered, stirring frequently, until sauce thickens into gravy consistency, 5-10 minute If sauce is too thick, stir in additional chicken broth or water. Remove bay leaf and stir in parsley. Add salt to taste, if needed.
Spoon gravy over pork chops. Extra gravy may be served in a bowl on the side. (Recipe makes almost 3 cups gravy.).