Steps
1. In a bowl, combine olive oil, balsamic vinegar, honey, garlic powder, onion powder, and salt and pepper to taste.
2. Add the cubed lamb to the marinade and mix to combine. Cover the bowl and marinate for at least 1 hour or overnight.
3. Preheat the grill to medium-high heat.
4. Thread the lamb cubes onto the skewers and grill for 5-7 minutes on each side, or until cooked through.
5. Meanwhile, in a bowl combine the yogurt, mayonnaise, lemon juice, grated cucumber and chopped mint. Mix to combine and season with salt and pepper to taste.
6. Serve the grilled lamb skewers with the tzatziki sauce on the side.