Pre-heat a pan or sauce pot over medium heat, add your oil, then add your garlic and fry for a good minute.
Season the sauce to taste with salt and pepper, then set aside.
Cut the tops of the bell peppers off, cut out the middle core part that holds all the seeds to hollow out the bell peppers. Then, just use a spoon to scoop out the remaining seeds and the white pith.
Use your clean hands to mix the turkey and the breadcrumbs together in a bowl.
Add about 1 tablespoon of your canola oil, then add your ground turkey without overcrowding the pan (if you need to add the turkey in 2 batches, do so). Once the turkey is nice and browned, transfer to a new clean bowl and set aside.
At this stage, preheat your oven to 200 degrees C (400 F)
Turn the heat on the pan down to about medium heat, add a touch more oil, then add your onions and fry for about 1 minute. Next, add your garlic and fry for another 30 seconds, then add your chicken stock.
Bring the stock to a boil, then turn it down to a simmer and let the stock bubble for a few minutes. If there are any brown bits in the bottom of the pan from frying the meat, try to use your wooden spoon to clean the bottom of the pan (all of that residue can give the filling a lot more flavour).
Once the stock has simmered for a few minutes, add about 2-3 tablespoons of your tomato sauce to the mixture and stir it through.
Put the rest of your tomato sauce in a deep baking dish (or something similar), then spread it out evenly.
Put the lid on top, or if you don't have a lid, cover with foil.
Bake in the oven for 45 minutes covered. After 45 minutes, take the lid/foil off, put your grated cheese on top of the stuffed peppers and then bake uncovered for another 15 minutes.