Cut and clean out bell peppers. Season the inside with a pinch of salt.
Preheat oven to 350ºF.
In a pan on medium-hi heat, add canola oil and sauté pancetta and onion for 4 minutes. Add apples and continue to cook for 2 minutes until soft. Stir in maple syrup then remove mixture to another bowl and set aside.
Add ground pork, salt, pepper and sage to pan, breaking up meat with back of a spoon. Cook, stirring, until fully cooked, about 5-8 minutes.
Add tomatoes with liquid and simmer for 2-4 minutes until most of the liquid is gone. Take off the heat and stir in pancetta mixture, quinoa and feta.
Stuff mixture into prepared bell peppers, pressing down firmly. Sprinkle the fontina cheese over each filled pepper. Bake for 35-45 minutes until peppers are soft and cooked through.