Creamy Chicken & Penne alla Vodka Casserole with Peas

Bring a medium saucepan of water to a boil. Add penne and cook according to package directions. Drain.

Position rack in the upper third of oven. Preheat broiler to High.

Meanwhile, heat 1 tablespoon oil in a large broiler-safe skillet over medium heat. Add onion and cook, stirring, until softening and starting to brown, about 3 minutes. Sprinkle chicken with salt and pepper. Add the remaining 1 tablespoon oil to the skillet. Add the chicken and cook, stirring, until almost cooked through, about 5 minutes. Add tomatoes and peas; cook, stirring, until the tomatoes start to break down, about 2 minutes. Stir in vodka sauce and the drained pasta; cook, stirring, until hot and the chicken is cooked through, about 3 minutes.

Remove from heat and sprinkle with mozzarella. Broil until the cheese is melted and browned in spots, 2 to 3 minutes.