Cut the loin into large cubes.

Make a marinade with the mustard, honey, olive oil, orange and lemon juice, black pepper and grated garlic, and put half of this sauce in a bowl with the meat cubes, cover and refrigerate for 1 hour.

Cut the onions into pieces and push the skewer through each piece of onion and meat.

Prepare the grill with plenty of coal and place the skewers over the embers, painting them with the sauce left.

Cook all sides for a couple of minutes until they turn golden brown and serve!