that's it, let's do it with resin. I had a couple of week-ends spent in the forest with my kids, having an eye at everything that could look like a mud puddle (easy these days). So well, here is my technique for today: Epoxy resin! The Gedeo brand as usual, easely findable in Europe, not too much bubbles.. I tinted it with oil paints as usual, a mix between transparent and opaque ones..
The thing is "how to do mud like nobody else" really, there is so much mud around in nowadays panzer modelling ;)