This was my wife's requested model and I couldn't find perfect model anywhere, but remixing LightBringer was the easiest way. This is 15mm tall, if you need taller, you can just change Z size in your slicer.
I will add more photos once wife has made the cookies.
NOTICE:
Even though your filament might be food safe, the 3D printing process is not food safe! Use at your own risk!
If you print this with PLA, don't machine wash it and use only hand warm water.
EDIT:
Wife reguested finger holes for easier cookie removal from the mold. .STL upgraded!
The author remixed this model.
I changed the @LightBringer's model so that there is heart shaped hole inside.