adapted from Epicurious
1/4 cup pine nuts (optional)
1 medium fennel bulb, stalks and fronds removed, and base trimmed
6 ounces red butter lettuce, roughly chopped
6 ounces frisée, torn into 2-inch pieces
1/2 cup fresh mint leaves
3 tablespoons extra-virgin olive oil
3 tablespoons red wine vinegar
1 tablespoon finely chopped shallot
1 teaspoon coarse-grain Dijon mustard
Salt & Freshly ground black pepper
Heat oven to 350°F with rack in middle.
Spread pine nuts in a small baking sheet and bake until pale golden, about 8 minutes. Let cool.
Using mandoline (or very sharp knife), thinly slice fennel bulb crosswise, beginning at base, into a large bowl, stopping about halfway up bulb (reserve remaining bulb for another use). Toss fennel with lettuce, frisée, and mint.
Whisk together oil, vinegar, shallot, Dijon mustard, and 1/4 teaspoon each of salt and pepper in a small bowl.
Toss salad well with vinaigrette and pine nuts. Season to taste, if necessary, with salt and pepper.