In a bowl combine the envelopes of mixes together. Sprinkle on top of the roast. Pour in 1/2 cup warm water. Cook on low for 6-7 hours or until tender.
The gravy is nothing but thickened roast juices. Transfer the pot roast juices to a small pot and whisk in the cornstarch and water slurry (1 Tablespoon cornstarch and 2 Tablespoons of COLD water). Bring to a boil to activate the thickening agents of the corn starch. Serve over pot roast.