Menards has the Blackstone Griddle Cutting Board on clearance for $9.99 discounted from $22.99. Pick up in store, shipping is also available from a store with stock.
Product description is below.
This premium quality koa wood cutting board is specifically designed to be used with Blackstone® griddles. You can set this cutting board directly on your griddle top and protect your knife's edge from the solid steel.
Brand Name: Blackstone
Specifically designed to be used on a Blackstone flat top griddle
4 wooden feet to protect the cutting board from direct heat
Premium quality koa wood construction
Use to let meat rest while other food cooks