fresh zucchinis (firm and shiny) • generous pinch of sea salt • ground meat (try a mix of beef and pork) (300 g) • red bell pepper, finely chopped (for color and sweetness) • chopped fresh parsley • large egg (helps bind everything together) • whole wheat breadcrumbs (or oats for more fiber) • homemade tomato sauce • shredded Manchego cheese (the secret to a perfect gratin) (60 g)