Step 1: Bring a large pot of salted water to a boil. Add the pasta and cook according to package directions until al dente. Reserve 1 cup of pasta water before draining. Drain the pasta and set aside.
Step 2: In a large skillet or Dutch oven, heat 1 tablespoon of olive oil over medium-high heat. Add the sliced andouille sausage and cook until browned and slightly crispy, about 5-7 minutes. Remove the sausage from the skillet and set aside.
Step 3: Add the remaining 1 tablespoon of olive oil to the skillet and reduce the heat to medium. Add the diced onion and bell peppers. Cook until the onion is translucent and the peppers are tender, about 5 minutes.
Step 4: Add the minced garlic to the skillet and cook for 1 minute, until fragrant. Stir in 1/2 tablespoon of the Cajun seasoning and the red pepper flakes (if using). Cook for 30 seconds, allowing the spices to bloom.
Step 5: Stir in the tomato paste until well combined. Pour in the chicken broth and bring to a simmer. Reduce the heat to low and stir in the heavy cream or coconut milk. Whisk until smooth and creamy.