Beet greens are tasty and nutritious but quite fragile, so you should try to cook them within a day or two of purchasing your bunched beets. This recipe is a rustic one from "Molto Italiano" by Mario Batali. Warning - make double the quantities, this soup is quite addictive!
Soften 2 cloves of diced garlic and a slivered onion in 1/2 cup olive oil. Add 2 medium potatoes cut into 1/2 inch dice, salt and hot red pepper flakes, then add 4 cups beet greens sliced into 1/2 inch wide ribbons and 3 cups water and a bay leaf. Bring to a boil and them simmer for 15-20 minutes.
Mario says to serve with toasted Italian peasant bread and grated pecorino romano; feel free to forsake if you are keeping strict paleo, or substitute with gluten-free bread options if you have some leeway.