In a bowl or container, whisk together the olive oil, lemon juice, water, Dijon mustard, and honey (if using) until fully combined and emulsified. This wet base creates the foundation for the marinade. Add the oregano, garlic powder, salt, and black pepper, stirring well to distribute the dried seasonings evenly throughout the liquid. I like to taste the marinade at this point—a quick dab on your finger lets you adjust the salt or acidity if needed before the chicken goes in.

Add the cubed chicken to the marinade from Step 1, stirring gently to coat all pieces evenly with the mixture. Cover the container and refrigerate for at least 3 hours (or up to overnight for deeper flavor). The acid from the lemon juice will begin to tenderize the chicken while the mustard and garlic penetrate the meat, creating a flavorful, juicy result.

Preheat your grill to 425°F. Remove the chicken from the refrigerator about 10 minutes before grilling to allow it to come closer to room temperature for more even cooking. Working in batches if necessary to avoid crowding, place the chicken pieces on the hot grill grates. Cook for approximately 5 minutes on the first side without moving them—this develops a nice caramelized crust and locks in the marinade's flavors.

Flip each piece of chicken and cook for another 5 minutes on the second side. The chicken is done when it reaches an internal temperature of 165°F at the thickest part—I always use an instant-read thermometer to ensure it's fully cooked but still tender. Let the chicken rest for 3-5 minutes off the heat before serving; this allows the juices to redistribute, keeping the meat moist and flavorful.