Preheat the oven to 350 F.
Roast the nuts in a shallow baking pan in the middle of the oven. Toasting should take 10 to 12 minutes. Wrap the nuts in a kitchen tower and rub them to remove the skins from the nuts. Cool the nuts and chop coarsely.
Rub the cut sides of the garlic thoroughly inside a large salad bowl.
Prepare the grill for cooking or preheat the broiler should be preheated.
Thread the mushrooms horizontally onto skewers and arrange on a baking sheet.
Whisk together vinegar and salt in a small bowl, then whisk in the olive oil gradually until it is emulsified.
Brush some vinaigrette onto the mushrooms and grill about 4 to 6 inches off of glowing coals, turning once, until the mushrooms are golden and tender. This should take 3 to 5 minutes. As an alternative, the mushrooms can be broiled.
Working fast, remove the mushrooms from the skewers and slice into ¼ inch pieces. Add to the salad bowl with the frisee, the rest of the vinaigrette, the truffle oil, and salt and pepper to taste.
Toss well and serve immediately.