Radish greens, as you'd imagine from the taste of their root vegetable, are more bitter and acerbic than kale or beet greens, but you can cook them the same way. The leaves are a little more delicate than the former two, so they don't need to be cooked as long. But how to tame that bitterness?
Acid. A little lemon juice or red wine vinegar goes a long way in perking up and balancing the earthy, assertive flavor of radish greens. The radishes, on the other hand, become sweeter and less pungent when roasted, making them a natural complement to their greens.
When I'm not in the mood to think too much, I just put vegetables on top of polenta. It provides a hearty base and pairs well with nearly anything you can think to put on top.
Which is precisely what I did with this bunch of radishes from the first week of my CSA share. The solution for my remaining radishes and greens and a lazy Saturday (it's hard to get anything done when this guy wants to play with you) was to roast the radishes and greens, possibly one of the easiest ways to cook vegetables, throw them on top of polenta, and add a few easy seasonings at the end. Simple, tasty, and, moreover, not a bit of waste.
Polenta with Root to Stalk Radishes
vegan if not using cheese; gluten-free
1 cup low-fat milk (use water to make this vegan)
1 cup water
1/4 teaspoon salt
1/8 teaspoon freshly ground black pepper
1 bunch radishes (including the greens)
2 tablespoons olive oil
1 teaspoon freshly-squeezed lemon juice
1 tablespoon grated pecorino cheese (omit to make this vegan)
1/4 teaspoon flaky salt, such as Maldon (optional)
Add the polenta, milk (if using), water, and salt and pepper to a small sauce pan. Cover, bring to a boil, then turn down the heat to medium-low. Cook partially covered, stirring occasionally, until the polenta is thick and cooked through, about 20 minutes.
In the meantime, cut the greens off the radishes. Wash and dry the greens, then coarsely chop the stems and leaves. Toss with 1 tablespoon olive oil and salt and pepper.
Wash the radishes and cut them into 1" pieces (if using large radishes) - you can leave small ones whole. Toss with the remaining 1 tablespoon oil and a few pinches of salt.
Spread the radishes on one baking sheet and spread the greens on another. Roast the greens until the leaves are crisp and the stems are tender, 5-7 minutes. Roast the radishes until they are slightly blistered and golden in spots, 10-12 minutes.
Divide the polenta between two bowls. Top each one with half of the radishes and greens. Sprinkle each serving with half of the lemon juice and finish with half of the cheese and a sprinkle of salt.