In a large Dutch oven, heat 2 tablespoons of olive oil over medium heat. Add sliced smoked sausage and cook for about 5-7 minutes until browned and slightly crispy, stirring occasionally. Remove the sausage from the pot and set it aside, leaving the flavorful oil behind.

Using the same pot, add chopped onion, diced red bell pepper, and sliced celery. Sauté these veggies for 4-5 minutes until they soften and the onion becomes translucent. Add minced garlic and cook for an additional minute until fragrant.

Melt 3 tablespoons of butter in the pot with the softened veggies. Whisk in 3 tablespoons of flour and cook for 2-3 minutes, stirring constantly until bubbly and slightly golden.

Gradually pour in 4 cups of chicken broth and 1 cup of half and half, stirring continuously. Once combined, add peeled, diced russet potatoes and 2 tablespoons of Cajun seasoning. Bring to a gentle boil, then reduce heat to low and simmer for about 20-25 minutes until the potatoes are tender.

Once potatoes are tender, return the browned sausage to the pot. Fold in 1 cup of shredded sharp cheddar cheese until fully melted.

Ladle the soup into warm bowls and sprinkle with freshly chopped parsley for garnish. Serve immediately alongside warm cornbread or crusty bread.