How to Make It
Prepare a charcoal or gas grill for moderately high heat or preheat a ridged grill pan over moderately high heat. Brush 1 tablespoon of the olive oil over the endives, radicchio and romaine, then sprinkle with salt and pepper.
Grill the lettuces, turning occasionally, until they are crisp-tender and browned in spots, about 6 minutes.
Coarsely chop the lettuces. In a large bowl, toss the lettuces with the vinegar and the remaining 2 tablespoons of olive oil. Season the salad to taste with salt and pepper. Serve warm.