1. Make the marinade by whisking together the zest, lemon juice, grape-seed oil, salt and pepper. Set aside.
2. Cube all of the vegetables and put into a large ziplock bag.
3. Cube all of the chicken and put into a large ziplock bag.
4. Pour a little more than half the marinade in with the vegetables and the remaining in with the chicken. Shake the bags well and once it’s all coated well, pour the veggies out onto a sheet tray or in a large bowl so that you can easily grab them to skewer.
5. Start skewering, adding each vegetable and chicken and intermixing them. Yellow Zucchini, Red Onion, Chicken, Green Zucchini, Tomato, Chicken… repeat. You want the vegetables and chicken fairly close but make sure to keep some space especially around the chicken so that heat can distribute evenly and fully cook it.
6. Once your skewer is done, place it in the bottom of a casserole dish. Continue skewering until all the vegetables and chicken have been used. It’s okay if you have some vegetable-only skewers at the end.
7. Pour the remaining liquid from each bag/bowl back onto the skewers. Wrap tightly and marinate overnight or until ready to use.
8. When ready to cook – cook on a hot grill and cook until the chicken reaches 165ºF, about 10-15 minutes total, rotating every 5 minutes to get even char marks. Garnish with balsamic and basil when ready to serve.