How to Make It
Combine onions, garlic, thyme, and bay leaves in a large saucepan. Add 12 cups water and 1 tablespoon salt. Cover and bring to a boil.
When onion mixture is boiling, remove lid and stir in rice. Return to a boil and cook, uncovered, for 10 minutes. Add farro and cook for 10 minutes. Add quinoa and cook for 8 minutes.
Drain through a fine wire-mesh strainer, shaking well to remove any excess water. Transfer grains to a rimmed baking sheet, spreading out to cool, and season with pepper and remaining 1 teaspoon salt. When cool, discard any large pieces of onions, garlic, thyme, and bay leaves.
TO FREEZE: Portion grain medley into resealable bags and stack flat in freezer.
TO THAW: Place frozen grain medley in a microwavable bowl; discard freezer bag. Microwave on high in 1-minute intervals until warm. Or reheat in a pan on stovetop.