Bring a large pot of lightly salted water to a rolling boil; stir in the rigatoni and cook at a boil uncovered, stirring occasionally, until the pasta has cooked through but is still firm to the bite, about 13 minutes. Drain.
Meanwhile, cook the beef mince, garlic, onion and capsicum in a large pot over medium-high heat until the beef mince has browned and the vegetables are tender, about 7 minutes. Pour in the tomato sauce and salsa; season to taste with salt and pepper. Bring to a simmer. Reduce heat to medium-low and continue cooking 15 minutes.
Stir in the Cheddar cheese and cream; cook and stir 3 minutes then stir in the sour cream until evenly blended. Add the drained pasta and stir until heated through.