Stir Together The Flour, Rosemary, Mustard, Salt, Garlic Powder, And Pepper In A Bowl. Dredge The Pork Chops In The Seasoned Flour, Shake Off Excess, And Set Aside. Heat The Vegetable Oil In A Large Skillet Over Medium-High Heat. Add The Pork Chops And Cook Until Golden Brown On Both Sides, About 4 Minutes Per Side. Place The Onion, Mushrooms, And Garlic Into A Slow Cooker. Add The Seared Pork Chops, Then Pour In The Cream Of Mushroom Soup And Marsala Wine. Cover, And Cook On Low Until The Chops Are Tender, 6 To 8 Hours.