Crock Pot Balsamic and Onion Pot Roast

Ingredients (11)

• 2 large onions, cut in thick slices
• 4 large carrots, cut into 3 inch pieces
• 1 parsnip, cut into 1 inch pieces
• 2-3 lb. pot roast
• 2 Tablespoons steak rub (I used McCormick's Montreal)
• 2 Tablespoons olive oil
• 1 1/4 cup beef stock
• 1/2 cup balsamic vinegar
• 1/2 cup tomato sauce
• Leftover broth from crockpot
• 1 Tablespoon cornstarch dissolved in 2 Tablespoons water