pete's guide to grilling fruits & vegetables asparagus place directly on the grill over high heat for 2 to portobello mushrooms brush them lightly with olive oil and place gill- and cook for an additional 7 minutes zucchini thinly slice lengthwise and coat lightly with olive the grill for about 1 minute peaches serve with greek yogurt watermelon cut the watermelon into big wedges or 1" thick pineapple grilling pineapple cuts the fruit's acidity and the pineapple into wedges or rings and place it on the grill for about 3 minutes per side