Place pasta in a large pot of boiling water. Plan to strain pasta when it’s JUST about tender enough, but in the meantime:
In a large saucepan, brown sausage. Add celery, onion, and green pepper; saute until tender. Remove from pan, set aside.
Add butter to pan, stir until melted. Sprinkle rice flour over melted butter; cook – stirring frequently – until the flour paste (roux) turns a golden brown. (Go darker if you’re comfortable with making roux!).
Carefully add white wine to pot – it will steam violently – and whisk until smooth. Add chicken broth, milk, cayenne powder and herbs, continue whisking until once again smooth. Season with salt and pepper to taste.
Add sausage and vegetable mix to the pot, along with strained pasta. Cook over medium heat until some of the liquid is absorbed by the pasta, and it is as tender as you like it. Add shrimp, stir, and heat just until shrimp is cooked through.
Serve hot, sprinkled with green onions.