In a food processor, combine the cashews and almonds into crumb sized pieces. Add the dates and salt and process again to form your base mixture. Press the mixture into a lined 22cm cake tin (preferably with a removable base for easy removal).
Drain and rinse your soaked cashews well then add them to a high-powered blender or food processor, along with the remaining ingredients. Blend until completely smooth.
Pour into the base and smooth out the top. Place in the freezer to set for a couple of hours, or just leave it in the fridge overnight. When ready to serve, top with fresh berries and lemon if desired. Let soften out of the freezer if it has frozen completely.
Keep this cheesecake cool as it will soften at room temp.