To Cook: Sprinkle 1 teas. salt in a large skillet, set over med. high heat and brown the roast well on all sides. Remove roast to slow cooker. Add the onion to the skillet and brown lightly, stirring often. Pour in the wine: scrape up pan juices and turn into the slow cooker with the salt and pepper. Cover, turn to Low and cook 10-12 hours. Before Serving: Skim 2 Tab.. fat from the liquid in the cooker and heat in a medium skillet over low heat. Stir in the flour to make a smooth paste. Then add the cooking liquid all at once; stir continuously until the sauce is smooth and has thickened about 5-7 min. Remove skillet from heat; stir in the sour cream. Serve sauce over the pot roast.