PREP: Preheat the oven to 350 F / 175 C. Line a 9 x 9 inch / 23 cm x 23 cm baking dish with parchment paper.

PULSE: Add the cassava flour to the bowl of a food processor. Sift the tigernut flour through a fine mesh sieve into the food processor bowl and discard any large pieces left behind at the end. Add the arrowroot, honey & salt. Pulse a few times to combine. Add the chilled palm shortening to the food processor bowl. Pulse a few times in short bursts until the mixture begins to resemble crumbs. Don’t over process: you want to have visible pieces of fat flecked throughout and too much pulsing will overheat and melt the shortening. Add the ice water and pulse a couple of times to distribute it evenly. The finished dough should look very crumbly, but hold together when pinched between your fingers.

PRESS: Divide the dough mixture into two portions, setting aside 2/3rds of it for the base of the crumble bars and reserving the remaining 1/3rd to make the crumble topping. Pour the base mixture into the lined baking dish and use your hands to press it evenly into a single layered crust.

SET: Place the baking dish into the preheated oven and bake for 10 minutes, until the crust has just set, but not taken on any color. Remove from the oven and set on a trivet to cool slightly while you make the filling.

THICKEN: Add the cherries, strawberries, honey & lemon juice to a saucepan over medium heat. Bring the fruit mixture to a gentle simmer and cook until the fruit just begins to soften and the liquids reduce by about half, about 15 minutes. Make the arrowroot powder into a slurry with a little water, then add that to the fruit filling, stirring through to mix it through evenly. Cook for another few minutes, until the fruit mixture thickens and is no longer liquid-y, then remove from the heat.

LAYER: Spoon the fruit filling onto the top of the par baked crust and spread in an even layer. Take the reserved dough mixture from earlier and use your hands to gently squeeze it into small, streusel-like clumps. Sprinkle the fruit mixture with the crumb topping evenly. If you like, sprinkle the top with coconut sugar for a little extra crunchy contrast.

BAKE: Return the baking dish to the oven and cook until the fruit mixture bubbles and the crumble topping is barely just beginning to take on a little golden hue, about 25 minutes. Remove from the oven and transfer to a trivet to cool completely.

COOL: The bars are easiest to cut once they have cooled and been refrigerated for long enough that the crust firms up nicely. Cut into 16 squares. Store in the fridge for up to 3 days or so.