Bring a large pot of salted water to a rolling boil. Add the penne pasta and cook according to package directions until al dente, approximately 10-12 minutes. Drain and set aside.

In a large skillet, heat the olive oil and butter over medium-high heat. Add the shrimp and season with Cajun seasoning. Cook for about 3-4 minutes until pink and opaque, then remove from skillet.

Lower heat to medium-low, pour in the heavy cream, and stir constantly for about 2-3 minutes until thickened slightly.

Gradually add the Parmesan cheese, stirring until fully melted and smooth, about 1 minute.

Add the drained penne pasta to the skillet and toss to combine, heating through on medium-low for about 1 minute.

Serve immediately, garnished with additional Parmesan cheese and black pepper.