Spinach and Roasted Red Pepper Gratin

This rich, flavorful gratin dish makes a fantastic light supper or lunch main course. It also happens to be gluten-free and kosher for passover — go figure.

Spinach and Roasted Red Pepper Gratin
adapted from Epicurious

4 10-ounce bags fresh spinach leaves
3 red bell peppers
1 1/2 tablespoons butter
1 1/2 tablespoons olive oil
3 medium leeks (white and pale green parts only), thinly sliced (about 3 cups)
1 large shallot, chopped (about 1/4 cup)
3 garlic cloves, minced
1 cup whipping cream
4 large eggs
1 cup part-skim ricotta cheese
1/2 cup grated Swiss cheese
1/4 cup grated Parmesan cheese
1 1/2 teaspoons salt
1/2 teaspoon ground black pepper

Heat large deep nonstick skillet over medium-high heat. Working in batches (about 10 cups at a time), sauté fresh spinach in dry skillet until bright green and wilted, about 2 minutes per batch. Transfer spinach to strainer. Squeeze spinach dry; roll in kitchen towel to remove excess water.

Char peppers directly over gas flame or in broiler until blackened on all sides. Enclose in paper bag; let stand 10 minutes. Peel, seed, and slice peppers into 1/4-inch-wide strips.

Melt butter with oil in heavy large skillet over medium heat. Add leeks, shallot, and garlic; cook until soft, about 5 minutes. Remove from heat. Whisk cream and eggs in large bowl to blend. Whisk in all cheeses, salt, and pepper. Stir in spinach, leek mixture, and 2/3 of roasted red peppers (reserve 1/3 of peppers for topping). (Can be prepared 1 day ahead. Cover and refrigerate.)

Preheat oven to 350°F. Generously butter 13x9x2-inch baking dish. Transfer spinach mixture to prepared dish. Bake gratin until knife inserted into center comes out clean, about 50 minutes. Arrange remaining red pepper strips decoratively atop gratin and serve.