Blitz the gluten-free graham crackers into fine crumbs in a food processor, or place them in a zip-top bag and crush them with a rolling pin.

Combine the crumbs and melted lactose-free butter in a bowl until evenly mixed.

Press the crumb mixture into the base of a 20 cm round springform pan or cake ring lined with a strip of acetate or baking paper. Refrigerate while you prepare the filling.

Whisk together the cornstarch, sugar, agar powder, passion fruit purée, and mango purée in a bowl.

Cook in a saucepan over medium-low heat, whisking constantly, until thickened. Remove from the heat and let the cream cool for about 10 minutes.

Whisk in the vegan butter while the cream is still warm until fully incorporated. Add the vegan cream cheese and mix until smooth and homogeneous. For an even silkier texture, blend with an immersion blender.

Transfer to a container or bowl and cover with plastic wrap. Refrigerate for 1 hour.

Prepare the vegan meringue: whisk together the potato protein, xanthan gum, and cold water until the powders are fully dissolved (an immersion blender speeds this up), then refrigerate for at least 15 minutes. Pour the chilled mixture into the bowl of a stand mixer, add the pinch of xanthan gum, and whip until soft peaks form. Add the sugar one spoonful at a time, whipping on high speed, until the meringue is glossy and holds stiff peaks (6 to 10 minutes). Use immediately.

Spread the chilled mango-passion fruit cream over the prepared crust. Smooth the surface evenly with a spoon or spatula. Refrigerate while you make the vegan meringue. Reserve 50-90 g of the mango cream for piping on top.

You can also freeze the cake while you make the meringue. If the cake is frozen, the cake ring will be easier to remove.

Remove the cake ring and transfer the cake to a cake board or serving plate. Pipe the meringue over the top of the cake using a round tip. Pipe the remaining mango-passion fruit cream over the meringue.

Lightly torch the meringue with a kitchen blowtorch for an appetizing caramelized finish.

Return the assembled cake to the refrigerator for at least 30 minutes to set. Decorate with diced fresh mango just before serving.