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

Heat a large skillet over medium heat and add a drizzle of olive oil. Add your choice of chicken or shrimp; sauté for about 5-7 minutes until fully cooked and golden brown. Remove from skillet and keep warm.

In the same skillet, lower the heat and add Cajun seasoning, stirring for about 30 seconds. Pour in cream and stir. Simmer for 2-3 minutes until thickened. Add cheese if desired, stirring until melted.

Add the drained penne and cooked protein back into the skillet. Toss everything together for about 2 minutes, then add chopped bell peppers.

Adjust seasoning as needed. If sauce is too thick, add a splash of reserved pasta water. Serve hot garnished with extra cheese or fresh herbs.