I served this with corn bread, pan-roasted green beans, and white rice.

1 14-oz link smoked sausage (I used light)
1/2 cup canola oil
1 cup all-purpose flour
3 ribs celery, roughly chopped
1 onion, roughly chopped
1 large bell pepper, seeds removed and roughly chopped
2 large cloves garlic, peeled and halved
8 cups chicken broth or water or some combination of both (I used half/half)
1 teaspoon kosher salt
freshly ground black pepper to taste
2-3 teaspoons Tony Chachere's Creole Seasoning
6 green onions, thinly sliced
2 pounds peeled, cleaned raw shrimp with tails removed (16/20 size)
hot cooked white rice for serving

1. Heat your oven to 400. Line a baking sheet with foil and spray it with non-stick spray. Cut the sausage link in half lengthwise and then into 1/2-inch pieces. Place the pieces on the prepared baking sheet in a single layer and bake until browned, about 15 minutes. Set aside.

2. While the sausage is cooking, combine the oil and flour and mix well in a large pot. Heat over medium heat until the roux is a deep caramel color, stirring very often, 30-35 minutes. 

3. While the roux is cooking, put the celery, onion, bell pepper, and garlic in a food processor fitted with a metal blade. Pulse 2 times for 3 seconds each time and scrape down the sides of the bowl. Pulse 2 more times, 3 seconds each time, scraping down the bowl after each pulse. The veggies should be finely minced but not pureed.
4. Add the veggies to the roux and cook, stirring often, for 5 minutes (the roux is very hot, please watch for splatters).

5. Add the browned sausage, broth/water, salt, pepper, and Tony's seasoning. Bring it to a boil, reduce the heat to maintain a simmer, and cook, partially covered, for 45 minutes.

6. Add the green onion and shrimp, and cook 2-3 minutes or until they are just barely pink (they will continue to cook as they sit in the hot soup, so don't overdo it here). Serve over white rice.

This makes a ton of gumbo. We easily get two meals out of a pot.