Did that last year for my other hobby. More functional than aesthetic, I guess. Or maybe both. 2-sided 3d machined 3.5" deep. It was a challenge with the 4" long 0.25" bits. They chattered and screamed like crazy but got the job done. This is definitely 1/2" or bigger bit territory.
Preparing the material. The sheets are aligned with dowel rod.
Clamping and roughing. The steel square is the guide for flipping the block.
Machined from the back and finished.
Installed. I would have liked to keep the plywood texture but chickened out. To avoid layer separation in use (engine heat) I laminated glass/epoxy on the outside and painted it black.