BROWN THE BEEF AND ONION in oil in the open pressure cooker. Add salt and pepper, half cup wine, seal cooker and cook at 10 pounds pressure for 15 minutes per pound. Reduce pressure, open cooker and remove meat. To make gravy, remove all but 2 tablespoons fat from the cooker, add the flour and stir for 1 minute, then slowly add the wine and stock and simmer for a few minutes until thickened. Season gravy with salt and pepper to taste.