Soak the cashews by adding them to a mixing bowl and cover them with boiling hot water. Let rest for 1 hour. Rinse and drain thoroughly.
Preheat the oven to 350F/175C and line a 9x9 inch baking dish with parchment paper (use a piece that is big enough so it hangs over the sides for easy removal after baking).
Add oats, almonds, sea salt and coconut sugar to a high speed blender and mix on high into a fine meal.
In a medium mixing bowl stir to combine the oat-almond meal, maple syrup and coconut oil (start with just 4 tbsp) until a loose dough has formed. If the dough is too dry, add more coconut oil (starting with 1 tbsp).
Transfer the mixture to the lined baking dish and spread evenly. Place a piece of parchment paper on top. Use a coffee mug (or other flat bottomed object) to compact the dough by pressing down firmly until it is well packed.
Bake for 20 minutes or until the edges are golden brown. Remove from the oven to cool off slightly in the pan. Leave the oven on though.
Add soaked then drained cashews to a high speed blender together with scooped out coconut cream, lime juice and zest, sea salt, arrowroot powder and maple syrup. Mix on high until creamy and smooth. Taste the filling and add more lime juice or maple syrup if you feel it is missing some. I like mine to be more limey and tangy and not overly sweet.
Now pour the filling on top of the baked crust. Spread out evenly. Tap on the counter to remove any air bubbles. Slide into the oven.
Bake for 20-25 minutes. The edges should feel dry, the center should still be jiggly, but not liquidy any more. Take out of the oven and let rest for 10 minutes.
In the meantime prepare the passionfruit layer by adding passionfruit juice+seeds to a saucepan. Heat it up and at the same time make a paste by mixing arrowroot powder and water. Now add the paste to the saucepan and stir to combine. The sauce will thicken straight away. Take off the heat.
Once both the filling and the passionfruit sauce have cooled off a bit, pour the passionfruit mixture on top of the filling and refrigerate uncovered for at least 4 hours (but I recommend to let it sit overnight so the flavors can intensify).
To serve, slices into 16 even bars (or 9 if you want to go big). Leftovers can be stored covered in the refrigerator for up to 4 days.