We got a bunch of radishes in our first CSA box of the season which had the radish greens with the radishes. The radish tops were much too nice to just toss into the compost. I found this recipe for Radish Top Soup on allrecipes.com that I adapted. It is a tasty soup that's very easy to make.
Another use for the green tops are in green smoothies. I tried it today with a another bunch of radish tops that I had. I used the greens (about 2 cups), 1 cup each of mango and pineapple (frozen), 2 bananas and some vanilla almond milk. The greens added color but didn't change the flavor of the fruit.
2 tablespoons olive or sunflower oil
1 cup (approx.) chopped onions
3 green onions or you could use 1 or 2 green garlic stalks
3/4 cup chopped celery
2 medium potatoes, coarsely chopped
4 cups raw radish greens (if you don't have enough you could add turnip tops or spinach)
3 cups of chicken or vegetable broth
1/3 cup heavy cream (or 1/2 & 1/2)
5-6 sliced radishes
Sauté onions in the oil until tender. Mix in the other vegetables. Add the broth and bring to a boil. Reduce heat and simmer 20-30 minutes or until the vegetables are tender. Add salt and pepper. Blend with immersion blender or blend in batches in a blender. Return the soup to pan and add cream. Serve topped with sliced radishes which add a nice crunch. Taste to see if the soup needs additional seasoning.