Preheat the oven to 350°F & grease & parchment line a half sheet pan 12" x 18"
For the cake batter cream the softened vegan butter with the sugar on medium to high speed until light & fluffy, this may take about 4 minutes.
Combine the flax meal with the aquafaba & whisk smooth, let stand 5 minutes to thicken.
Combine the extract & vinegar with the coconut milk
Sift the flour with the baking powder, cornstarch & salt .
Now add 1/3 of the dry ingredients to the creamed butter mixture on low speed mixing just enough to combine before adding the next addition
Next add half of the coconut milk then another 1/3 of the dry ingredients
Then the last of the milk & the last of the dry ingredients
Now add the coconut flakes & mix well
Spread the batter into the greased & parchment lined cake pan & bake immediately in the preheated oven for 15 minutes then turn the temperature down to 325°F for another 12-15 minutes or when a toothpick inserted into the center comes out with soft crumbs
Cool in the pan to COLD (you can freeze for ease of handling)Carefully remove the cake layer to a cutting board to cut it into 4 equal pieces *see video tutorial
For the Mango Topping: In a medium sauce pot combine the sugar with the cornstarch then add the water & whisk to a smooth slurry, bring to boil whisking constantly to avoid scorching
Remove from heat after a full boil add the rum extract *optional then pour over the chopped mango in a large mixing bowl & stir to combine, refrigerate to cool then use as a topping & filling for your cake
Prepare your choice of vegan whipped cream
Video
Notes
Storage: Coconut Mango Cream Cake must be kept refrigerated at all times and will stay fresh wrapped loosely for up to 5 days