Preheat your oven to 350 degrees Fahrenheit.
Cut a piece of parchment paper to fit a standard baking sheet.
In the food processor, grind your cashews, flour, and 1/2 teaspoon salt as finely as you can.
Slowly drizzle water about one tablespoon at a time into the ground mixture while PULSING the food processor until you have a soft, crumbly mixture that can be nicely pressed into a dough.
Shape by rolling into a circle with diameter the width of your parchment paper.
For the filling, slice 3 medium apples about 1/8 inch thick.
Toss apples with date sugar, lemon juice, a pinch of salt, and cinnamon.
Arrange apples on pie dough, leaving a border about two inches all the way around, then fold border over the fruit to complete your galette shape.
Bake at 350 degrees for 45 minutes or until lightly browned.