Preheat oven to 350º F. If using a baking sheet, line with foil. If using a traditional loaf pan line with parchment paper so you can lift out and drain the grease before slicing.
Heat a large skillet over medium high heat. Add the oil and swirl to coat. Add the onion and bell pepper. Cook for 5-6 minutes until they are soft and the onions are translucent. Let cool slightly.
In a large bowl mix together all of the ingredients for the meatloaf. Use your hands to get the mixture to be evenly combined. Shape and place in your prepared pan.
Bake for 45 minutes.
Meanwhile combine the ketchup, brown sugar, and mustard together for the glaze.
Remove the meatloaf from the oven and top with the glaze. Return to the oven and bake for another 15-20 minutes, until it reaches 155º F.
Let the meatloaf rest for 10-15 minutes. Carefully use the parchment paper to lift the meatloaf from the pan, letting the grease drain back into the pan.
Slice to serve.
