I'll buy 5/4 to make these, circular, 1" finished thickness, 16" diameter, edge-glued pieces, a milled round-bottom groove near the perimeter for catching juice drippings.
The best I see for sale on Amazon are black walnut. I can get about anything and am thinking claro walnut, a little heavier and harder than black walnut.
But the choices are endless. What might work and look best?