Preheat the grill to medium-high heat and place a cast-iron skillet in one corner of the grill.
Toss the zucchini, eggplant, bell peppers, onions, and peaches with the olive oil, and sprinkle everything but the peaches with salt, then place directly on the grill along with the corn.
Add the ghee to the cast iron skillet along with the cherry tomatoes and toss to coat.
Close the grill lid and cook for 8 minutes, until the side directly on the grill is charred, then flip and cook the veggies for an additional 7 minutes, until charred and softened. Remove from the grill and sprinkle with cracked black pepper, then serve!