The cake is sprinkled with a flammable but edible crumbs. There are also identically colored crumbs which are not flammable. Upon ignition, the flammable toppings burn away, revealing the message or picture spelled by the non-flammable toppings.

Ideally these crumbs would be made from something very thin, about a millimeter square in size so that they would catch fire quickly from neighboring crumbs and leave very little material behind.

Inspired from a very half-baked dream where’s the cake had multiple layers of these that could be burned away and revealed in succession. I’m not sure how to achieve more than one layer, though.
-- cowtamer, Feb 27 2023

This is brilliant. Fire on a cake is already a standard thing with candles. This takes it to the next level. [+]
-- doctorremulac3, Feb 27 2023


I approve of all process based work that results in the production of legible text as an outcome. (have posted several myself but not using fire yet)
-- xenzag, Feb 27 2023


The multiple layers thing could be done if you could find suitable materials with staggered flashpoints and combustion temperatures. You would also need temperature-specific matches to light them with though. (a bit like different grades of solder and an adjustable iron)
-- pocmloc, Feb 27 2023


Excellent!
-- calum, Feb 27 2023


This will result in more idiots being hospitalized than gender reveals. I heartily approve!
-- 21 Quest, Feb 27 2023


Ooh, can one layer be a contract with the devil?

To layer this, you would need to have edible varieties of foods that combust at different temps, or the inside is sufficiently insulated for a bit before bursting into flame.
-- RayfordSteele, Feb 28 2023



random, halfbakery