I was just looking for something to do with the seafood I had in my freezer, I found a bag of tortellini in there too and we were in business. Just kinda made this one up from stuff I had in the kitchen one day. We decided it was worth making again.
Cook tortellini according to package directions, drain and set aside. Meanwhile, melt half of the butter in pan and cook shrimp and diced onion, just until onions are tender and shrimp is pink. Remove shrimp & onions to a warm plate, reserving pan drippings.
Add more butter to pan, melt and add flour whisking until well blended with butter. Gradually pour in milk, whisking constantly. Add parmesan cheese, salt & pepper. Stir over medium heat until thick and bubbly.
Combine all ingredients in a pan except the colby-jack cheese. Mix thoroughly.
Sprinkle with colby jack and heat just until the cheese is melted. Serve with crusty garlic bread.