01 - If using wooden skewers, submerge them in water for at least 20 minutes to prevent burning during grilling.
02 - Heat grill to medium-high, approximately 400°F.
03 - Melt butter in a small saucepan over low heat. Add minced garlic and cook briefly, about 1 minute, until aromatic. Remove from heat and mix in chopped parsley, lemon zest, salt, and black pepper.
04 - Alternate zucchini slices, bell pepper, and red onion pieces on prepared skewers.
05 - Generously coat assembled skewers with half the garlic butter mixture.
06 - Place skewers on preheated grill. Cook 3 to 5 minutes per side, rotating occasionally, until vegetables are tender and lightly charred.
07 - Transfer skewers to a serving dish and immediately brush with the remaining garlic butter. Garnish with lemon wedges and serve warm.