Soak Cashews in cold water for 4 - 6 hours.
Drain and rinse cashews and add to blender with 250ml water, wholegrain mustard, nurtional yeast and half a teaspoon of salt, bilitz on high speed until a smooth and creamy. Refridgerate until needed.
Chop potatoes into small cubes. Add to a large pot of well salted water, bring to the boil.
Chop shred cabbage, and add to the boiling water along with the pasta, cook for 8 - 10 minutes as per pasta cooking instructions.
Gently saute the leeks, and garlic, with olive oil over medium-low heat until softened. Add the cashew cream, juice of one lemon and apple sauce, and stir to combine.
Strain the pasta, cabbage and potato mixture, reserving about 200ml of the cooking water.
Add the reserved pasta water to the creamy leeks, and season well with salt and pepper.
Throughly toss the pasta, cabbage and potaotes through the creamy sauce, and serve immediately.