Bring a large pot of salted water to a boil and cook the penne according to package directions until al dente; drain in a colander and set aside.
While the pasta cooks, heat a large saucepan over medium heat and melt the butter.
Add the minced garlic and sauté until fragrant, about 30 seconds to 1 minute, being careful not to brown it.
Whisk in the flour until blended to form a roux, then gradually whisk in the chicken broth and evaporated milk until smooth.
Bring the sauce to a gentle boil, stirring frequently, and cook 2 minutes or until it thickens.
Stir the cooked shrimp, shredded Parmesan, minced parsley, and seafood seasoning into the sauce and heat just until warmed through.
Place the drained penne in a large bowl, pour the shrimp sauce over the pasta, and toss to coat evenly.
Serve immediately.
