First start with soaking the cashews in water. Soak for at least 4 hours. Overnight ensures a very smooth texture.
Once soak, puree cashews and water they were soaked in, in a high pressure blender. You may need to divide in half and blend half at a time. Transfer into a large bowl.
In a small bowl mash strawberries with sugar. Depending on how sweet you want the strawberries, use anywhere from 2-4 tbsp of sugar. Mash with a fork or pastry blender until desired consistency.
In cashew puree stoir in vanilla, salt, and sweetner of choice. Mix well. Add in strawberries and stir. Place in freezer safe container and cover.
Let freeze all the way through. Best served after it has set out at room temperature for 5-10 minutes.