Porcini mushroom powder gives savory depth to the nutty brown butter bagna cauda dressing in this wintery salad.

Ingredients

• ½ cup unsalted butter (4 ounces), at room temperature
• 1 cup extra-virgin olive oil
• 12 anchovy fillets (from 1 [2-ounce] can), chopped (about 2 tablespoons)
• 10 medium garlic cloves, smashed
• 1 tablespoon porcini or hen-of-the-woods mushroom powder
• 4 medium-size (6-ounce) cara cara oranges or satsuma mandarin
• 2 medium shallots (about 2 1/4 ounces), thinly sliced (about 1/2 cup)
• ¼ cup sherry vinegar
• 1 teaspoon honey
• ½ teaspoon himalayan pink salt
• 1 large (9-ounce) head pink radicchio (la rosa del veneto), trimmed and leaves separated
• 1 large (9-ounce) head castelfranco radicchio, trimmed and leaves separated
• ½ teaspoon flaky sea salt, plus more to taste
• ½ teaspoon black pepper, divided
• 2 ounces parmigiano-reggiano cheese, shaved (about 1 cup)

Directions

1. Melt butter in a small saucepan over medium-low. Cook, stirring occasionally, until butter starts to foam and turn brown, about 8 minutes. Remove from heat, and stir in oil. Let cool slightly, about 1 minute. Return to heat over low; add anchovies and garlic. Cook, stirring occasionally, until garlic softens, about 10 minutes. Add porcini powder, and cook, stirring occasionally, until flavors meld and anchovies melt, about 5 minutes. Remove from heat, and gently mash garlic with a fork to incorporate. Set aside.
2. Juice 1 orange to yield 1/4 cup orange juice. Stir together 1/4 cup orange juice, shallots, sherry vinegar, honey, and pink salt in a small bowl. Let stand at room temperature until flavors meld and shallots soften, about 10 minutes.
3. Meanwhile, carefully remove peels from remaining 3 oranges, using a sharp knife to cut along the curve of each orange, removing as little flesh as possible; discard peels. Slice peeled oranges crosswise into 1/2-inch-thick rounds, and set aside.
4. Place pink radicchio leaves and Castelfranco radicchio leaves in a large bowl. Pour orange juice mixture over radicchio leaves, and toss thoroughly using your hands. Add orange rounds, flaky sea salt, and 1/4 teaspoon pepper; gently toss. Season with additional flaky sea salt to taste.5. Drizzle 3 tablespoons warmed brown butter–porcini bagna cauda evenly over salad. Top evenly with cheese and remaining 1/4 teaspoon pepper. Serve salad alongside remaining brown butter–porcini bagna cauda.