Place roast in 4 Quart Stock Pot. Sprinkle with seasoned salt, pepper and onion soup mix or sliced onion, if desired. Do not add water.
Cover unit and place on Slow Cooker Base. Simmer on Setting #4 for 2 1/2 to 3 hours or on Setting #2 for 7 to 10 hours or until roast is well-done and tender. Meat juices may be used for gravy. Keep warm on Setting #1.
Preparing the Gravy
Remove the roast from the pot and place the pot over medium heat on your stove top. Pour off all but 2 tablespoons of the roast drippings.
Add the flour to the water in a small bowl and mix to dissolve. The consistency should be like a thin paste.
Pour the flour mixture into the pot with the drippings and whisk into the drippings.
Stir until the gravy begins to thicken. As it thickens, slowly add your desired liquid (water, beef stock, milk or cream). Alternate stirring and adding liquid, maintaining the consistency you want, for about 5 minutes.