Clean and prepare the vegetables. Deseed the bell pepper and remove the white part. Then, cut it into 1-inch squares. Peel the onions and cut them into 8 wedges each.
Dice the pork loin into 1-inch cubes, trying to keep the size consistent for a better result.
Assemble the skewers by alternating one piece of meat and one piece of vegetable. In the end, you should have around 8 skewers.
Lay the skewers on a large tray and toss with coarse salt, extra virgin olive oil and black pepper. Add rosemary and sage. Cover and set aside for at least 20 minutes.
Preheat the grill on medium-high heat.
When the grill is nice and hot, add the skewers and cook for 15 minutes, rotating them one quarter at a time.
While cooking, you can spread the marinade on the skewers using the rosemary sprig as a brush.