Spinach and Roasted Red Pepper Gratin

Name: Spinach and Roasted Red Pepper Gratin
Ingredients: 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