HVP French Onion soup

Wanting to run french onion soup but with limited space and a higher volume of soup, what's the easiest way to get good melted/crispy cheese on top. Our salamander is electric not like a real fire breather so it's slower and pretty inefficient especially with other things we use it for. My best thought is a quality blow torch on expo but if anyone has any other good ideas i'd love to know.