In a medium pot set over a medium heat, warm the soy milk, water and vegan butter/shortening/refined coconut oil/olive oil until the fat has melted.
500 ml (2 cups) unsweetened soy milk, 100 ml (1/2 cup) water, 100 g (7 tbsp) vegan butter, vegetable shortening (e.g. TREX), refined coconut oil or olive oil
Add the grated potatoes, nutritional yeast, garlic granules, smoked paprika and mustard to the pot and stir. Bring up to a boil then turn down the heat to let it simmer for 10-15 minutes until the potato is completely soft.
300 g (2 medium) potatoes, 3 tbsp nutritional yeast, 1 tsp garlic granules, 1/2 tsp smoked paprika, 2 tsp American mustard
Remove from the heat and add the vinegar and marmite/soy sauce/miso paste. Blend until smooth using a stick/immersion blender (or a jug blender) then taste and season with salt and black pepper. We suggest being quite generous with the salt here, start with 1/4 to 1/2 tsp and go from there! Remember that cheese contains quite a lot of salt so it's key to getting the right flavour.
4 tsp malt vinegar, 1 tbsp marmite or dark soy sauce or miso paste, salt and black pepper
Your sauce is now done - enjoy it hot or allow to cool at room temperature and store in a lidded container in the fridge for up to 3 days, or the freezer for up to 3 months.