Cook the pasta according to the package directions in a large pot of boiling water. Drain.
Meanwhile, heat a non-stick skillet over medium heat.
Toss the shrimp with the olive oil and the Cajun seasoning.
Add the shrimp to the skillet and cook for about 4 minutes, flipping once, until they are completely pink.
Set aside and keep warm.
In a medium saucepan, over medium heat, melt the butter.
Add the garlic and cook, stirring for about 30seconds, until fragrant.
Whisk in the flour, and cook, whisking constantly, until it is lightly browned, about 1 minute.
Slowly whisk in the milk, stirring until it is incorporated and smooth.
Add the thyme, oregano, salt, pepper and parmesan and whisk continuously for 3-4 minutes until the sauce has thickened slightly.
Reduce the heat to a low simmer until the pasta is ready.
Toss together the pasta and alfredo sauce and serve with the Cajun shrimp on top.
Garnish with parsley and additional parmesan if desired.