Although it is great in a salad—sweet and bitter at the same time—in the cold winter months, radicchio trevisano is better cooked, and has a more resilient texture. Traditionally paired with speck – boneless, smoked prosciutto – radicchio makes a great risotto (see Risotto with Radicchio) and a great sauce for pasta. In those dishes, the radicchio serves a secondary role as a distinctive flavoring but when baked this way, it is the main protagonist. I enjoy baked radicchio by the mouthful, savoring its taste and texture, sweet, bitter and crunchy.
The best variety for baking is the long thin radicchio Trevisano (as shown in the photos) but the small, round heads most often found in the supermarket—known rosa di Chioggia in the Veneto—or the kind with long but wide leaves (resembling purple Romaine lettuce), are also delicious baked this way. Serve as an antipasto or vegetable course, over soft or baked polenta.
- 1-1/2 pounds round head radicchio (radicchio di Chioggia), 2 or 3 firm heads
- 4 tablespoons butter
- 4 tablespoons extra-virgin olive oil
- 3 plump garlic cloves, smashed and peeled
- 1 medium-large onion, peeled and sliced in 1/4-inch thick half-moons (2 cups)
- 1 teaspoon coarse sea salt or kosher salt or to taste
- 1 tablespoon red wine vinegar
- Freshly ground black pepper to taste
- 1 cup freshly grated Grana Padano
Trim the radicchio heads, discarding wilted or bruised outer leaves and slicing off the very bottom if tough and discolored (don’t remove the core). Slice the heads in quarters or sixths, into wedges about 3-inches wide. Cut through the core, so the leaves are held together. Arrange a rack in the center of the oven and heat to 375°.
Put the butter and 2 tablespoons of the olive oil in the skillet and set over moderate heat. When the butter is melted and foaming, stir in the onions and garlic and cook for a minute, then lay in all the radicchio wedges in one layer. Sprinkle on the salt, cover the pan and cook slowly, turning the wedges over and stirring the onions every couple of minutes.
After 10 minutes or so, when the radicchio is softened slightly but still firmly holding its shape, stir the vinegar and 1/4 cup water together and pour into the pan. Raise the heat a bit, bring the liquid to the boil, turning the wedges and stirring. Cook for a couple more minutes until the pan juices are reduced and syrupy and the wedges are lightly caramelized.
Remove the skillet from the heat and arrange the radicchio wedges in the baking dish in one layer. Spoon the onions all around and pour the skillet liquid over. Drizzle on the remaining 2 tablespoons olive oil, season with freshly ground black pepper, and sprinkle the grated cheese in an even layer covering the radicchio.
Tent the dish with aluminum foil and press it against the sides. Bake covered for about 20 minutes, remove the foil and bake another 5 minutes or more, until the radicchio wedges are tender and moist and glazed golden on top.