Directions

1. In a large bowl, whisk eggs, cream, 1/4 cup Romano cheese and 1 teaspoon salt.
2. In a 10-in. skillet, heat 2 tablespoons oil over medium-high heat. Add mushrooms and onion; cook and stir until tender. Add basil, garlic, pepper and remaining salt; cook and stir 1 minute longer. Transfer to a bowl; stir in mascarpone cheese and remaining Romano cheese.
3. In same pan, heat 1 tablespoon oil over medium-high heat. Pour in 2/3 cup egg mixture. Mixture should set immediately at edges. As eggs set, push cooked portions toward the center, letting uncooked eggs flow underneath.
4. Let stand, covered, 5-7 minutes or until completely set. Remove to a serving platter; cover and keep warm. Repeat with remaining egg mixture making two additional frittatas, using remaining oil as needed.
5. Place one frittata on a serving platter; layer with half of the mushroom mixture. Repeat layers. Top with remaining frittata. Cut into wedges.