In looking at my kippah decorated to look like matzah, a child asked me: "Is this real matzah?" This got me thinking: Does halacha say anywhere that matzah has to be flat? It's easy enough to prepare it and cook it on a curved surface.
Matzah does not need to be flat. It also does not need to be thin. At some point and time in Jewish history people used to even draw or make designs on their matzah before baking, but this practice has long since been forbidden
Matzah can be up to a tefah (handbreadth) thick. I would not recommend anyone make a matzah so thick as you run a real risk of having the center be uncooked which is hameitz.
Technically matzah can be made into any shape you want, but in our days we rule that anything that interrupts the process of making matzah is usually forbidden. In ancient times an artisan would make the matzah and once the dough was ready but not yet cooked they would quickly draw a figure in the matzah. This additional step of adding a design to the matzah as a separate and interrupting part of the matzah baking process is no longer allowed. If someone were to stop and interrupt the matzah practice to shape the dough in a similar way I could imagine it being forbidden.
Here is a scenario in which I don't think there'd be any halakhic issues with shaping the dough.
- You are working the dough which is most likely already in a ball shape. You could just bake that ball shape and see what happens. You could corner it and make it into a square, or maybe you even roll it out into a snake. All of those are part of "working the dough" so I see no issue with their shape other than ensuring your oven is hot enough to cook the dough all the way to the center.
Here is a scenario in which I think there would be a potential halakhic issue
- You are done working the dough and you have a mold next to you that you'd like to use to shape the dough. You break off a piece of matzah from the main ball of dough and put in mold and let main matzah dough sit while you finish molding the first piece. This more than likely would not be allowed. Or if you have a big mold and you want to push the whole dough in it but then the dough sits in the mold temporarily for the shape to take, or if you bake it in the mold, there may very well be halakhic issues.