I like curves and figured timbers and I thought a curved frame and panel would be an interesting challenge. figured maple paired with lacewood. Mortise and tenon joinery, oil and polyurethane finish.
I created a template of the curved frame. The joinery is mortise and loose tenon. I left the outside of the pieces square until the inside was complete and glued up with the panel in place. To rout the grove and flush trim the interior I dry fit the pieces together and with my air nail gun attached some scrap in areas to be cut away later to hold it all together for routing. Plenty of double stick tape on the template helps too.