Season the brisket all over.
Place your brisket in your slow cooker pot.
Pour in the 500 mls of stock carefully on top of the brisket and cook on Low for 9 hours.
Cook on Low for 8-9 hours.
Remove carefdully from pot when cooked and place on a chopping board to rest. I do check by plunging a carving fork or similar if it is soft at this point. Experience will tell you if it's soft enough. I know that comes with time but it should be ready by now.
I carefully pour the gravy that's left in the pot into a saucepan being sure to use oven gloves to hold the pot.
My easy cheat here is to sprinkle in gravy granules to thicken the amazing gravy. Sprinkle in 4 tbsp at first and stir with the whisk. Bring the gravy up to a simmer and stir whilst it thickens. If the gravy is not thick enough then add more gravy granules a couple of tbsp at a time.
If you don't have gravy granules then you can use a corn flour slurry. Simply mix the corn flour with the water so that all is dissolved and swirl it through the gravy as you bring to a simmer and it thickens. Add another slurry mix if it does not thicken enough.
Season the gravy to taste.
Slice the brisket. It may crumble a little so I tend to slice it thickly with a sharp knife. See in the notes for tips.
Serve with the best gravy ever! Loads of it.