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1
Preheat oven to 400 degrees F (200 degrees C).
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2
Line a baking sheet with parchment paper.
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3
Place 2 cups Parmesan cheese into a shallow bowl.
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4
Fill a large pot with lightly salted water and bring to a rolling boil over high heat. Once the water is boiling, stir in penne and return to a boil. Cook the pasta uncovered, stirring occasionally, until the pasta has cooked through but is still firm to the bite, about 11 minutes. Drain well in a colander set in the sink.
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5
Dip chicken breasts into the beaten egg whites.
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6
Press chicken into Parmesan cheese in shallow bowl to coat both sides.
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7
Gently toss between your hands so any cheese that hasn't stuck can fall away. Place the chicken on prepared baking sheet.
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8
Bake chicken breasts in the preheated oven until no longer pink in the center and the juices run clear, about 18 minutes. An instant-read thermometer inserted into the center should read at least 165 degrees F (74 degrees C).
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9
Meanwhile, heat Alfredo sauce, diced tomatoes, tomato sauce, and red pepper flakes in a large saucepan over low heat. Allow to simmer while you finish the remaining steps.
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10
Heat a large skillet over medium high heat; cook and stir mushrooms and spinach until mushrooms are tender, about 5 minutes.
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11
Stir vegetables into the sauce.
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12
Place the penne pasta into a serving bowl; slice chicken breasts and arrange over the pasta.
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13
Pour sauce over the pasta and chicken, and sprinkle remaining 1 cup Parmesan cheese on top.
