SCF, I like Kris Dhillon's gravy base. I sometimes throw some carrots or whatever leftover veggies I have into the base as well. For me it comes out looking more or less like a watered down carrot and coriander soup, kind of a dull orange brown colour, and quite liquid. If you're slowly adding the gravy into a ripping hot pan it will reduce down quickly and caramelise the sugars nicely