Surface Soup

I had an interesting experince last weekend. I was fishing a pond which was next to a race track and someone had thrown in a polysterene type cup in the water. It had some sort of soup in it and the lid was slightly broken but everytime the fish nudge it it leaked out some soup and the carp went mad..Everytime I managed to cast a crust near the cup it was wolfed down. My question is, is there any way we can created this surface film of soup( obviously more enviromental friendly)at a distance of about 25yds as it certainly turns the carp on feed .Elsewhere the carp show not the slighest interest in the bread.

The easy answer would be to dunk your crust in soup before you cast it out!!!

I tried that but it did not have the impact the orginal cup did. I was thinking more of a way to create a liquid surface groundbait at a distance. Is it easy and if so how do we do it ?

Freeze it and you will be able to fire it out miles...as it melts it will create a soup slick!
Another option is stuff some soup filled sponge in a feeder body

Spod out the soup with a pocket rocket. I've used boilie soups before and they can really fire the fish up. Very messy, very different and great fun.