4 large peppers, halved lengthwise, seeded
5 tablespoons olive oil, divided
6 ounces feta cheese, diced (about 1 1/2 cups), plus 2 ounces coarsely crumbled (about 1/2 cup) ** (Chevre is also a good substitute)
6 tablespoons cold water
1 small garlic clove, chopped
1 1/2 4.5-ounce bags mesclun salad
1 1/2 tablespoons Sherry wine vinegar
Kalamata olives (optional)
Preheat oven to 425°F. Place all peppers, cut side down, on large rimmed baking sheet. Drizzle with 2 tablespoons oil. Roast until peppers are tender and brown in spots, about 45 minutes. Remove from oven and cool 15 minutes on baking sheet. Peel peppers; cut each half lengthwise into 4 strips. Season to taste with salt and pepper. Place in small bowl. DO AHEAD Peppers can be made 1 day ahead. Cover and chill.
Place 6 ounces diced feta, 6 tablespoons cold water, and 1 tablespoon oil in processor; puree until smooth, about 1 minute. Add garlic and blend 2 seconds. Set dressing aside.
Place mesclun in large bowl. Toss with remaining 2 tablespoons oil, then vinegar. Season to taste with salt and pepper. Arrange greens on large platter; top with peppers. Drizzle feta dressing over and sprinkle with 2 ounces crumbled feta. Garnish with olives, if desired.