Let instant onion stand in water 5 minutes, then combine with butter and parsley, mixing well.
Slash bread on the bias in 1-inch slices, cutting to, but not through bottom crust.
Spread onion butter generously on one side of each slice.
Wrap loaf in foil.
Heat on barbecue grill 20 to 30 minutes or till hot, turning occasionally.
Or heat in moderate oven (350°) about 25 minutes.