The easiest option is to add them to a salad. This time of year the leaves are small and delicate and will make for a delicious peppery accent to most greens. As they get larger, coarser, and bitterer, it’s better to sauté them with olive oil and garlic until tender. Use them right away or stick them in the fridge for another time, they’ll keep for at least a week. They’re delicious as a room temperature side dish, or added to scrambled eggs, soup, or stew.
If you’re feeling more adventurous, try a radish leaf pesto, it’s definitely for lovers of all things bitter. For a less bitter pesto, use half radish and half spinach leaves. Happy summer!