Knead minced meat, egg, breadcrumbs and mustard. Season with salt and pepper. Shape into 4-5 cm balls. Quarter the peppers, clean, wash and cut into bite-sized pieces. Clean, wash and cut the zucchini into wide slices.
Wash the sage, shake dry and pluck the leaves from the stalks. Put 3 meatballs each on skewers, alternating with sage and vegetables. Cook on the hot grill while turning for about 10 minutes. Brush the skewers with olive oil and serve immediately. Tzatziki and flatbread are delicious with them