Chicken Souvlaki

Bahan-bahan (4 porsi)

• 4 boneless skinless chicken breasts (cubed into 1-inch cubes, about 1 ½ lbs)
• ½ onion (optional)
• ⅓ cup olive oil
• 3 tablespoons fresh lemon juice (about 1 lemon)
• 3 cloves garlic (crushed)
• ½ teaspoon dried oregano
• ½ teaspoon salt (or to taste)
• ¼ teaspoon black pepper