Next we heat a large pot over medium-low heat with the oil. When it is starting to get hot, we add the onions, stir, and cover to “sweat” while we prepare the rest of the ingredients.
We halve and seed the peppers and then thinly slice. We have about 2½ cups of bell peppers. We stir the onions and add the sliced peppers. We continue to cook, partially covered.
We smash the garlic cloves with the side of the chef knife (carefully) and discard the peels. We sprinkle with salt and mince, yielding ½ teaspoon of garlic. We add this to the softened onions and peppers, along with the oregano and pinch of red pepper flakes and continue to cook, stirring often.
Meanwhile, we insert two metal skewers into the sausage ring, in an x-shape, to keep the ring together on the grill. We put the sausage on the grill, cook for five minutes, flip for another few minutes, until cooked through.
While the sausage is grilling, we rinse and chop the tomato half. We add this to the cooked vegetables and continue to cook on low heat.
When the sausage is done, we quarter the bread and slice open. We grill the bread a few minutes on each side and top with the cooked onions and peppers. We remove the skewers from the sausage, cut into pieces and serve on the sandwiches. We quickly chop our parsley and sprinkle on top of the sandwiches with more red pepper flakes.