Wash, dry, and prep the onion, carrots, celery, red pepper, and zucchini. (Peel zucchini and carrots at this step, if desired.)
Add these to your crockpot.
Season with garlic, salt, pepper, and red pepper flakes.
Pour in broth and canned tomatoes (with their juice!)
Add frozen green beans.
Cook on High for 4 hrs or Low for 6 hrs.
Optional: For protein, add 1 c of cooked, diced chicken, a drained can of white beans, or c of cooked quinoa.
Taste and adjust seasoning to preferences, then serve. Garnish with fresh herbs or microgreens, or a drizzle of olive oil if desired.