Add bacon to a large pan then turn the heat to medium. Gently fry until crisp with the fat rendered down, then add to a 3.5L slow cooker, leaving excess fat in the pan.
Turn heat to medium-high then add peppers, onion, celery & garlic. Fry until it all softens & starts to colour. This step is important not only to develop flavour, but also to sweat out the moisture so the filling doesn't come out watery. Add beef & fry until browned, breaking up with your wooden spoon as you go. Add to the slow cooker.
Stir in crushed tomatoes, kidney beans, tomato paste, Oxo cube, Cajun seasoning, smoked paprika and ¼tsp S&P. Use your wooden spoon to level the top. Slice the baby potatoes to around ¼" thick then lay the slices over the filling, working from the outside in, overlapping as you go. Generously season with S&P then add lid & cook on HIGH for 3 ½ hours or LOW for 7 hours, or until the potatoes are very tender.
Remove lid, cover with cheese then add the lid back on for 5 or so mins until the cheese melts. If there's considerable water on the potatoes before you add the cheese, you can dab them with paper towel to remove some. If it's just oil I typically leave it there as it's flavour. Serve with sour cream if desired then tuck in!
