Add roast to slow cooker. Combine remaining ingredients and stir until well mixed then pour over roast.
Cook high for 4-6 hours, or low for 8 hours.
Whisk together cornstarch and water in a small dish and mix into slow cooker. Turn to high, add veggies, cover and cook another 10 minutes until veggies are tender crisp.
Serve over steamed rice and garnish with fresh parsley.