2 tablespoons extra-virgin olive oil
1 tablespoon cider vinegar
1 tablespoon minced shallot
1 1/2 teaspoons Dijon mustard
1 peeled, small-dice apple
1 small-dice roasted beet
3 cups coarsely chopped Treviso radicchio
1/3 cup crumbled blue cheese (optional)
Kosher or seasalt
Freshly ground black pepper
Instructions for roasting the beets:
Heat the oven to 375°F and arrange a rack in the middle. Rinse the beets and trim off any leafy tops. Wrap completely in aluminum foil and place in the oven. Roast until tender and easily pierced with a knife, about 1 to 1 1/2 hours. Remove from the oven and let cool.
When the beets are cool enough to handle, peel using a paring knife or by pushing the skin with your fingers.
Slice the beets, drizzle with olive oil, and season with salt and freshly ground black pepper.
Instructions for the salad:
Place the olive oil, vinegar, shallot, and mustard in a large, nonreactive bowl and whisk to combine. Add the diced apple and beet and toss until well coated in the vinaigrette.
Add the radicchio and blue cheese and season with salt and pepper. Toss to evenly combine, taste, and season with additional salt and pepper as desired.