1tablespooncornstarch per cup of liquid(for gravy)
Instructions
Cut off an inch or two piece of fat from the roast and chop into small pieces. Melt in a cast iron skillet over medium high heat. If the roast is very lean, use a tablespoon or two of vegetable/olive oil.
Rub the roast with garlic powder, salt and pepper. Sear the roast in the cast iron skillet once the fat has melted, until browned on all sides.
While roast is searing, chop vegetables. Carrots, potatoes and celery should be in about ½-1 inch chunks. The onion should be cut in half vertically, then cut in large wedges.
Toss the vegetables with the tablespoon of oil and parsley flakes.
Put the vegetables in the slow cooker. Then place the roast on top. If you have a temperature probe, insert it into the roast as directed by the slow cooker manufacturer.
For pan gravy, set aside the cast iron skillet. Do not clean it yet!
For medium rare cook roast until 140 degrees, approximately 2-2.5 hours on high, 4-5 hours on low. For medium cook until 145 degrees, or another 30 minutes to 1 hour.
Remove roast and allow to rest for 10 minutes before slicing. For crispier browned vegetables, place in a single layer on a baking sheet in a 450 degree oven for 10-15 minutes, turning once.
Measure the pan juices then pour into the cast iron skillet and loosen all browned bits.
In a small container combine 1 tablespoon of cornstarch for each cup of liquid with a small amount of water to dissolve. (If you have two cups of juices, use two tablespoons of cornstarch in about 2-3 tablespoons of water.) Whisk the cornstarch slurry in the juices and bring to a boil, stirring frequently. Boil one minute.
Notes
The times listed below were for my slow cooker. Yours may vary depending on the manufacturer, the capacity of the slow cooker and the amount of food inside. Consult your manufacturer's instructions for more information.