Heat your griddle pan until nice and hot.
Using a pastry brush, lightly brush the griddle pan with avocado oil (high smoking point) OR vegetable broth. To get a nice charred finish you do need to use a tiny bit of oil but the key is using it very sparingly as the burger itself already has a bit of oil inside so as the temperature rises it will come through.
Place patties on pan and cook on both sides until you have nice charred griddle marks but the burger is still pink inside.
Roughly 2 – 3 minutes either side.