Cut a quarter of an onion into cubes. Peel and chop the potatoes into ½ inch (1 cm) cubes.
Add onion and potatoes to pot and boil for 10 minutes, or until soft.
Remove potatoes and onion from the pot. Make sure to save the water.
Begin cooking fettuccine pasta in a separate pot.
In a blender, combine 1 cup (235ml) of the water used to boil the veggies, raw cashews, veggies, lemon juice, and seasonings. Blend until creamy. Add more of the boiling water if the mixture is too thick.
Add salt to taste and garlic.
NOTE: Adding 1 tsp of nutritional yeast, and ¼ tsp truffle oil will really make this dish pop with cheesy flavor!