Soak the cashews for about four hours or overnight.
Chop the almonds and roast them together with the sunflower seeds in a pan without oil until they start scenting. Let them cool afterwards. Roughly chop the dates and mix them with the sunflower seeds, almonds, oatmeal, coconut oil and salt until you get a sticky mass.
Spread the mass for the cake base in a small springform pan (20cm in diameter) and press it with a spoon. Now, finely blend the soaked cashews with coconut milk, maple syrup, lemon juice and half of the blueberries and fill it into the pan. Let the cake freeze at least for four hours in the freezer. In between, decorate the cake with the remaining berries.
Let the cake thaw for a few minutes before serving.