Preheat. Set your grill up for two-zone cooking with your overall target temperature around 400 degrees F.
Cook the sausage. Place a 4.5- or 6-quart Dutch oven over the direct flame side of your grill, place the butter in followed by the sausage. Break the sausage apart with a wooden spatula.
Add vegetables. Once the sausage begins to brown, add in the diced peppers, garlic, jalapeno, onions, and celery along with ½ Tablespoon of Fiesta seasoning. Stir it often but close the top of your grill in between stirs to maintain temperature. Cook the sausage and vegetable mixture for about 5 minutes, or until the onions are almost translucent.
Add remaining ingredients. Stir in the remaining spices, rice, stock, and white wine. Bring the contents of the Dutch oven up to a boil. Once boiling, cover the pot with a lid leaving about ½ inch vent open. Push the pot over to the indirect side of the grill, so there is no direct heat underneath to scorch the rice and close the grill lid.
Cook the jambalaya. Cook the rice for 35 to 40 minutes, checking on it every 10 minutes and fluffing it to prevent the bottom from burning. If it stops boiling and is “soupy”, put it back on direct heat.
Season the shrimp. When the rice is nearly cooked, prepare the shrimp. Mix 3 Tablespoons of melted butter and 1 1/2 Tablespoons of Fiesta seasoning in a small bowl.
Grill the shrimp. Skewer the shrimp then brush with the seasoned butter on both sides. Grill the shrimp skewers over direct heat for about 90 seconds per side or until they are no longer translucent. If the shrimp curl up into a tight, constricted circle, they are overcooked. They should be a nice shiny white with pink/red accents and a loose “C” shape.
Serve the grilled shrimp jambalaya. Taste the finished rice and season with additional salt and pepper, to taste. Remove the grilled shrimp from the skewers and place it on top of the finished rice, garnish with thin-sliced scallions and enjoy!