Place 3/4 cup cashews in a bowl and add enough water to cover; soak for 2 hours. Drain.
Blend 1/2 cup cashews in a blender until smooth. Stir blended cashews, coconut, and 2 tablespoons agave syrup together in a bowl until smooth; press into a small cake pan.
Blend soaked cashews in a blender until smooth. Add cocoa powder, coconut oil, and 3 tablespoons agave syrup; blend until smooth. Pour chocolate cake over cashew crust; refrigerate until set, 2 hours to overnight.