First, cut the andouille sausage into bite size pieces and sauté over medium heat until browned. Make sure the sausage gets nice and brown because this will add a deeper flavor to the risotto. Remove from heat and set aside.
Heat the butter in a 4 quart saucepan or dutch oven over medium heat. Add the onions and green peppers and sauté until soft, about 2 minutes.
Add the rice and cook for 1-2 minutes, stirring constantly, until the middle of rice kernels begin to turn white.
Add the browned sausage and sherry and cook until the liquid is fully absorbed, stirring continuously.
Add the tomatoes, Cajun seasoning, thyme and cayenne pepper and stir to combine.
Next, start adding the broth, ½ a cup at a time, stirring until each ½ cup is absorbed before adding the next ½ cup.
Continue until the last ½ cup of broth remains; reserve that last ½ cup.
Add the shrimp and cook until they just start to turn pink.
Add last ½ cup of broth, stir and serve immediately, garnished with green onions.