Preheat the oven to 190 C / Gas 5. Wash the potatoes and dry with kitchen paper then prick with a fork. Brush skins very lightly with olive oil (this makes the skins crispier).
Bake in the preheated oven until the potato is tender all the way through, about 1 hour.
While the potatoes are cooking, fry the smoked bacon (lardons) with the chopped garlic until crispy, then remove from pan leaving behind any excess oil. Add the spring onion and mushrooms to the smoked bacon oil and fry till softened, then remove from pan.
Once thoroughly cooked, cut the potatoes in half and scoop out the flesh leaving a 1cm shell. You need this thickness to ensure the skin doesn't break.
Mash the potato adding the bacon, mushrooms, spring onion, crème fraiche and sweet chilli sauce, mix well.
Spoon mixture into the skins then return to the oven until crispy, about 15 minutes. I generally cook garlic bread at this time.
Red onions are a perfect replacement for the spring onion if preferred.