In a large pot over medium heat, melt 2 tablespoons of butter.
Add the diced onion and cook for 3 to 4 minutes, until softened.
Add 1 teaspoon garlic and cook for 1 more minute.
Stir in the uncooked rice and 2 tablespoons of Cajun seasoning, coating the rice evenly.
Pour in the chicken broth and bring to a boil. Reduce heat to low, cover, and simmer for 20 to 25 minutes, or until the rice is tender and the liquid is absorbed.
While the rice cooks, heat olive oil in a large skillet over medium-high heat.
Add the sliced sausage and cook for 3 to 4 minutes per side, until browned and crisp. Transfer to a plate.
In the same skillet, reduce heat to medium and add the remaining butter.
Stir in the remaining garlic and Cajun seasoning and cook for 1 minute.
Pour in the heavy cream, scraping up any browned bits. Simmer for 3 to 5 minutes, until slightly thickened.
Add the cooked rice and sausage to the skillet and stir to combine.
Garnish with chopped parsley and serve warm.