Pat the pork chops dry with paper towels.
In a wide, shallow dish, whisk together the ⅓ cup flour, garlic powder, onion powder, paprika, 1 teaspoon salt and ½ teaspoon pepper.
In a large heavy duty skillet, such as a cast iron skillet, heat the olive oil over medium heat.
Once the pan is hot, dredge each pork chop in the flour mixture, coating both sides and gently shaking off any excess flour. Add pork chops to the pan and cook until browned on both sides, 4-5 minutes per side. Transfer pork chops to a clean plate and cover to keep warm.
Add the butter to the pan. Once melted, add the onion. Cook the onion, stirring often, for 3 minutes. Then add the mushrooms and cook, stirring often, for 7 minutes, until onions and mushrooms are very soft and browned.
Add the minced garlic and 2 tablespoons of flour and cook, stirring, for 30 seconds.
Pour in the broth and add the thyme, ¼ teaspoon salt and ¼ teaspoon pepper. Stir and scrape up any browned bits stuck to the bottom of the pan.
Return the pork chops to the pan. Cook for 4-8 minutes, or until the gravy has thickened and the pork chops are cooked through to 145° F when measured with an instant read thermometer. If the pork chops are very thick (thicker than 1 inch), it is best to cover the pan while they cook through and then uncover it for a minute or two to thicken the gravy. If the gravy thickens too much, you can stir in a little more broth to thin it out.
Stir in the heavy cream, if using. Serve pork chops topped with the onion and mushroom gravy.