Bring a large pot of salted water to a boil and cook the whole wheat penne according to package instructions until al dente.
While the pasta cooks, season the chicken breast with a pinch of salt and black pepper.
Heat half of the olive oil in a large skillet over medium-high heat and sear the chicken for 6-7 minutes per side until golden brown and cooked through.
Remove the chicken from the pan and let it rest for 5 minutes before slicing.
In the same skillet, add the remaining olive oil and the green peas, sautéing for 2 minutes.
Lower the heat to medium and pour in the marinara sauce and heavy cream, stirring constantly to create a smooth, pink sauce.
Drain the pasta and toss it directly into the skillet with the sauce until every noodle is perfectly coated.
Plate the creamy pasta and peas, top with the sliced seared chicken, and finish with a sprinkle of grated parmesan cheese.