Extreme Speed Baking

Consider that commercial industrial bakeries would be highly motivated to reduce baking time if it was feasible, at least in a money saving manner.

And yet the equipment for continuous process baking uses approximately the same temperatures and times used at home, just with continuous rather than batch oriented equipment, and with a higher degree of precision and ability to repeat consistently.

One therefore concludes that the traditionally known times are at least approximately optimal in terms of outcome and energy (or at least cost).

In some sense, cookies (historically, the word comes from a term for "little cake") are your speed baking answer. They bake in 12-18 minutes typically, compared to full sized cakes which bake in a time on the order of an hour.

By reducing the size of the food item, the time to cook through is reduced.

Very small cookies (thumbnail sized) can bake through in 5-8 minutes or so, but are terribly tedious and difficult to portion out accurately enough to get consistently good results at home.

A lot of timing in Baking is dependent on heat transfer through the material and governed by the laws of thermodynamics. The outer layers of the cookie in a way act as 'slow insulators' to delay the cooking of the interior. Beside that, the chemical action of the baking powder is fast enough to act within seconds so no problem there.

With traditional methods, you can't improve the heat-transfer inside the cookie (unless you run copper strips or other heat conducting materials which would moot the point).

However, since you're into extreme cooking, you may be able to do it in the microwave. Most microwaves have weird hotspots that are not easy to find and if you can manage them, I don't see why you couldn't bake a cookie the MW in 30 seconds or something.

Some other baked goods (cheetos, cheese puffs, and cheerios) are baked at very high speeds. I believe cheerios are in sub-seconds (come out of a nozzle in a hot oven, get clipped, and fall).