Winter is peak time for root vegetables like radishes. While the small salad-type radishes always say spring, these big guys are best in winter. And their intense spiciness is a good way to wake up a winter weary palate.
Pictured here are two types: The Black Spanish Radish (an ancient variety used medicinally over the ages) and the Watermelon Radish (or Chinese Radish) Though both are beautiful, for eating, these two types are quite different. Black Spanish radishes start out sweet but they have an intense horseradish-like hotness that can quickly reach out and rather rudely slap you in the mouth before retreating to a slow burn. Their spiciness mellows if they're salted and drained before eating.
If you're up for it, they can also be good French style—sliced paper thin, and eaten on brown bread with butter and salt. I think I'd add a slightly bitter dark beer. For salads, grate them and pair with sweeter roots like carrot and toss with champagne vinegar, salt and a pinch of sugar. Or cook them like turnips in stews or soups.
The Watermelon radish is an heirloom variety of daikon. These too are spicy, but a bit milder than the black radish. They're gorgeous on a crudités platter and make a nice foil for creamy rich dips. You may also slice them thinly and dress with toasted sesame seeds and rice vinegar. These are good sautéed and stir-fried.