Onion, Potatoes, Carrot, Fennel (really any veggies you might like), Herbs (rosemary and parsley are good ones), Olive Oil, Salt, Pepper
Cut veggies up into 1″ parts. Finely chop herbs. Combine in a bowl and add enough oil to lightly coat everything. Salt and pepper to taste. Using extra wide aluminum foil, make a packet with the veggies-burrito shaped works well. Make sure that the seams are well sealed so the juice doesn’t leak out. Cook on the grill for 20-30 min.