Make the cake.  Preheat oven to 350 degrees F/325 degrees F convection.  Line a 9 by 13 inch pan with parchment, coming up the sides, for easy removal.

In a large bowl, beat the oil, sugar, and vanilla until combined and slightly lightened in texture.  Beat in the egg yolks one at a time.  Stir in half the flour, followed by half the coconut milk.  Stir in the remaining flour along with the tapioca, baking powder, and cardamom.  Stir in the milk.

In a medium bowl, beat the egg whites until medium peaks form.  Fold the egg whites into the batter and pour into the prepared pan.  Bake 20-25 minutes until bouncy and a toothpick comes out clean or with a few moist crumbs.  Cool completely in the pan.

Make the filling.  In a medium bowl, whisk together the egg yolks, sugar, and tapioca.  In a medium saucepan over medium heat, place the milk, saffron, and vanilla bean seeds and pod.  Bring to a simmer before slowly whisking some into the egg mixture.  After about half the milk mixture has been added, pour the egg mixture into the pot.  Whisking constantly, cook until the mixture thickens into a pudding.  Pour into a bowl and whisk in the coconut butter.  Cover with plastic touching the pudding and refrigerate until chilled.

Once chilled, pass through a fine mesh strainer when ready to assemble the cake.

Make the crumble.  Preheat oven to 350 degrees F.  Line a baking sheet with parchment.  In a medium bowl, stir together flours, sugar, coconut, and cinnamon.  Mush in the oil until clumps form.  Spread onto the tray and bake about 15 minutes until golden brown.  Cool completely on the tray before breaking into pieces.  Crumble may be stored in an airtight container for up to 1 week.

When ready to assemble the cake, make the icing.  In a medium, microwave safe bowl, place the butter, milk, vanilla, cardamom, and honey.  Microwave on high in 30 second increments, stirring in between, until melted and combined.  If the mixture is too thick, stir in more milk.

Assemble the cake.  Cut the cake in half.  Place half on the serving platter of your choice.  Top with the pudding, smoothing into an even layer, leaving just a small border empty.  Top with a generous portion of the crumble, and enjoy the rest as a snack 😉  Place the other half of the cake on top, before pouring over the glaze and spreading to the edges.  Slice and serve or cover and store in the refrigerator for up to 3 days.