Rinse brown rice under running water in a mesh sieve until the water runs clear.
Spray crockpot with cooking spray, then add all ingredients except for frozen veggies, cheese and parsley. Give it a stir, then cook on high for 3 hours or on low for 6 hours.
Within the last 5 minutes of cooking time, microwave frozen veggies until defrosted for about 2 minutes, then grate cheese and chop up parsley if using.
Stir in veggies and cheese at the end of cook time, stirring well to combine. Serve garnished with parsley, and enjoy!
