Theory: Layer-Cake Desert isn't Edible

Arguments

 * Argument 1: Most of the other worlds in New Super Mario Bros. U are also named after foods. These include Sparkling Waters (Mint Archipelago in Japan), Soda Jungle, Rock-Candy Mines, and Meringue Clouds (Marshmallow Sea of Clouds in Japan). The only difference between these areas and Layer-Cake Desert, is the quality of their deceptions. The purple ‘Soda’ is obviously poison, the ‘Rock-Candy’ is actually crystal, and the ‘Meringue Clouds’ are just… clouds. Super Mario World shares a similar trope.


 * Argument 2: Looking closely, the ‘ice cream’ and ‘strawberries’ are actually just rock formations resembling them. The texture of the ‘ice cream’ looks like smooth marble with sharp cones poking out, while the ‘strawberries’ seem to be patchy igneous rocks. The ‘Layer-Cake’ surfaces of the desert are colored sands in stripe patterns, and the ‘frosting’ on the ‘cakes’ could be made out of a cement-esque material. The ‘cakes’ themselves are the most clearly inedible ‘desserts’ in the desert, as they contain ammonite fossils, which are only found in sediment (and are literally rocks).


 * Argument 3: Pretty much all of the edible dessert-themed stages throughout the Mario games have had a very high emphasis on making the sweets look especially delicious, and integrating them directly into the gameplay... [Examples: Cakewalk Flip, Cookie Cogworks, Cocoa Meltdown, Cookie Land, Sky-High Sundae, Super Mario 3D Lands World 3-5 and Special 5-4, Tart Top, Sweet Sweet Kingdom, Sweet Sweet Canyon, Sweet Sweet Galaxy, Sweet Mystery Galaxy, Sweet Dream, Peach's Birthday Cake, Dr. Mario Worlds World 12] ...The levels in the Layer-Cake Desert however don’t really care about the desserts, and shove them into the background, in favor of emphasizing the 🗿, among other clearly inedible structures and palm trees.


 * Argument 4: Layer-Cake Desert is also a course in Mario Golf: World Tour. If a golf ball comes into contact with a ‘cake’ in the desert, the ‘cake’ will behave akin to a sturdy earthen structure, rather than cake.


 * Bonus: The underground desert sections don’t even resemble sweets whatsoever, the truth under the surface is unveiled.