In a large skillet, heat the olive oil over medium heat. Add the diced onion, bell pepper, and celery. Sauté for about 5 minutes until the vegetables are softened.

Stir in the minced garlic and cook for an additional minute until fragrant.

Add the sliced smoked sausage to the skillet and cook for about 5-7 minutes, stirring occasionally, until the sausage is browned.

Stir in the shrimp and cook until they turn pink, about 3-4 minutes.

Add the rice, chicken broth, Cajun seasoning, thyme, black pepper, and cayenne pepper (if using) to the skillet. Stir well to combine.

Bring the mixture to a boil, then reduce the heat to low. Cover and simmer for 20-25 minutes, or until the rice is cooked and has absorbed the liquid.

Remove from heat and let it sit, covered, for 5 minutes. Fluff the rice with a fork and garnish with sliced green onions before serving.