Soak cashews overnight or quickly boil for 3 to 5 minutes to soften them.
Add all ingredients to a high-speed blender. Blend on high until the mixture is completely smooth. The goal is a silky, lump-free texture.
Pour the blended mixture into a medium-sized saucepan.
Place the saucepan over medium heat and start whisking. As the sauce heats up, the tapioca flour will start to thicken the sauce, giving it a classic, cheesy, and gooey texture. Switch to a spoon if it's too thick for the whisk.
Continue stirring or whisking for about 3 to 5 minutes. You’ll notice the sauce gradually thickening and becoming more cohesive. Be sure to keep stirring to avoid lumps and ensure an even texture. Turn off the heat and enjoy!
Store any leftovers in an airtight container in the fridge for up to a week. To reheat, add a splash of soy milk and stir again to bring it back to its creamy consistency.