Creamy chicken Alfredo bake combines tender pasta, rich Parmesan cream sauce, and juicy chicken in one irresistible casserole. This protein-packed family dinner is a guaranteed crowd-pleaser.
Preheat oven to 375°F. Grease a 9x13-inch baking dish to prevent sticking.
Cook penne pasta in a large pot of boiling salted water until al dente, about 1 minute less than package directions. Drain and set aside.
Meanwhile, season chicken breast with salt, pepper, and half the Italian herbs. In a large skillet over medium-high heat, melt 1 tablespoon butter. Sear chicken on both sides until golden and just cooked through (internal temp 165°F), about 5-7 minutes per side. Remove and dice into bite-sized pieces.
In the same skillet, reduce heat to medium. Add remaining butter and minced garlic; sauté until fragrant, about 1 minute. Pour in milk and heavy cream, stirring to loosen any browned bits. Gradually whisk in Parmesan until fully melted and smooth, then season with remaining Italian herbs.
Toss cooked pasta and chicken with the cream sauce until evenly coated. Transfer mixture to the prepared baking dish. Sprinkle mozzarella evenly on top.
Bake uncovered for 20-25 minutes, or until bubbling and the cheese is golden brown. Let rest for 5 minutes before serving for optimal creamy texture.