1-Make the marinade: Combine soy sauce, water, tomato concentrate, spicy ketchup, oil, honey, garlic, black pepper, and vodka in a jar; seal and shake for 20 seconds until glossy.

2-Soak wooden skewers: Submerge wooden skewers in water for at least 30 minutes to prevent scorching.

3-Prepare chicken and vegetables: Cut chicken breasts into large even cubes; cube bell peppers, quarter onions, and slice zucchini into thin strips with a peeler.

4-Thread pepper skewers: Alternate chicken, red and yellow bell pepper, and onion onto soaked skewers, leaving small gaps.

5-Thread zucchini skewers: Roll zucchini strips loosely and thread onto skewers alternating with chicken cubes.

6-Grill the skewers: Place skewers on a grill over medium-high heat (350–400°F) and cook for 10–12 minutes, turning every couple of minutes.

7-Baste with glaze: Brush the skewers generously with the reserved soy-honey glaze at each turn.

8-Check doneness: Remove skewers when chicken reaches 165°F internally and vegetables are nicely charred.

9-Apply final glaze: Brush on a final coat of glaze during the last minute on the grill; discard any leftover glaze that touched raw meat.

10-Rest and garnish: Let skewers rest for 5 minutes, then sprinkle fresh cilantro over the zucchini skewers before serving.