Black Radish Soup
Few crops stump people quite like the black Spanish radish, the spiciest of our winter radish offerings. Tasting like a horseradish root at half volume (it’s sometimes referred to as “Parisian horseradish”) and hardy and crisp enough to stay fresh for months in cold storage, it’s been adding a kick to cold season dishes across Europe since at least the 1500s. Cooking the radishes tames their bite, and with little more than a potato and other pantry ingredients you can make them into a fabulous creamy soup that tastes like mashed potatoes with a little extra dimension. Feel free to dress the soup up with more toppings like crumbled bacon, sour cream or crispy fried shallot or garlic, but a pat of good butter and a little grated raw radish is all it really needs.
1 Tbsp unsalted butter, plus more for garnish
1 medium white or yellow onion, chopped
2 cloves garlic, sliced
2 medium black radishes, peeled (about 1 lb), plus more for garnish, unpeeled
1 medium russet potato, peeled (about 8 oz)
¼ tsp salt, plus more to taste
⅛ tsp fresh ground pepper (white, if available)
3 ½ cups water
1 Tbsp prepared horseradish sauce
Heat the butter in a large saucepan over medium heat. Add the onion, and sauté 5 minutes, or until soft and translucent. Add garlic and continue cooking for another minute. Meanwhile, chop radish into ½” pieces and potato into 1” pieces.
Add the radishes, potato, salt, pepper, and 3 1/2 cups water. Bring the soup to a boil, reduce heat to medium-low, and simmer, covered, 30 minutes, until radish and potato are both easily pierced with a fork.
Remove soup from heat, stir in horseradish, and purée in a blender or with an immersion blender until smooth. Add up to 1 tsp salt, gradually, tasting often, to tame any bitterness. Serve topped with grated radish and a pat of butter, and maybe a cheesy soft pretzel on the side. Makes about 6 cups.