Step 1

Bring a large pot of water to a boil. Cook pasta until just tender, 8 to 10 minutes or according to package directions. Drain.

Step 2

Meanwhile, heat oil in a Dutch oven over medium heat. Add bacon and onion and cook, stirring occasionally, until beginning to brown, about 2 minutes. Add chicken, bell pepper, garlic, Cajun seasoning and pepper. Cook stirring, until the onion and bell pepper are beginning to soften, about 4 minutes.

Step 3

Add flour and stir to coat. Add tomatoes and their juice; bring to a simmer. Cook, stirring often, until the sauce is bubbling and thickened and the chicken is cooked through, about 2 minutes. Remove from the heat. Stir in sour cream.

Step 4

Stir the pasta into the sauce. Serve sprinkled with scallions, if desired.