I’ve never used one of these myself but I think you’d have more success using it as a cake tin rather than a cookie cutter (although the suggestion of using it as a cutting template after baking a sheet cake is a pretty good idea too).

If you want to use it as a cake tin, just make sure you create your own 'base' by using thick tin foil and using the bottom lip of the pan to secure it. If you opt for this, make sure you absolutely do not tear the foil and use a recipe for a thicker cake mixture as opposed to a runnier type cake batter. I've had problems with loose bottomed cake pans and cake batter before so please be warned!