Either pre-soak the raw cashews overnight or toss them in boiling water for 20 minutes. This softens the cashews and makes them easier to blend. This is especially important if you don't have a high powered blender (like a Vitamix).
Once the cashews have been softened, drain the excess water and add them to your blender with all of the other ingredients.
Blend everything until very smooth and creamy.
Store in the fridge.
If you need to heat it up, add it to a pot and slowly heat up on low heat.