To prepare dressing: Whisk creme fraiche (or sour cream), herbs, horseradish, salt and pepper in a small bowl until combined.
To prepare salad: Gently toss lettuce, watercress (or arugula) and mache (or mixed greens) in a large bowl. Toss with Herb & Horseradish Dressing to coat. Divide the greens among 4 plates. Flake 1 ounce trout over each salad and sprinkle with scallions and capers (if using).
Make Ahead Tip: Cover and refrigerate the dressing (Step 1) for up to 1 week.
Crème fraîche is a tangy, thick, rich cultured cream commonly used in French cooking. Find it in the dairy section of large supermarkets, usually near other specialty cheeses. Sour cream can be used as a substitute, or you can make your own lower-fat version by combining equal portions of reduced-fat sour cream and nonfat plain yogurt.
Mâche (“mosh”), also known as lamb's lettuce or corn salad, is a tangy green that resembles watercress. Popular in Europe, it is enjoyed in the first salads of spring. Look for it in specialty stores, large supermarkets and farmers' markets.
173 calories;13 g fat(7 g sat); 2 g fiber; 4 g carbohydrates; 10 g protein; 67 mcg folate; 30 mg cholesterol; 2 g sugars; 0 g added sugars; 3,132 IU vitamin A; 25 mg vitamin C; 81 mg calcium; 1 mg iron; 437 mg sodium; 325 mg potassium
Vitamin A (63% daily value), Vitamin C (42% dv)