Get some black slate tiles. Home Depot and Lowes has them a few dollars each.
Choose ones that are chipped a bit or have some texture on the surface. I think they look better for cheese plates when they're a bit rough.
Some custom tile places might have larger sizes and broken tiles which are perfect for this project.
Wash and let them dry over night. Put them in a 200 degree oven and turn it over to get them very dry.
Put a just a bit of the Mineral Oil on a dust free cloth. Go very light. Rub that into the slate. Let it dry a day or two and repeat. Do this about three time. Remember to use very light coats or the oil will clump up.
Let it dry a few days to harden. Wrap this up with kitchen twine and include a box of dust free chalk.
Use the chalk to write the names of the cheeses and meats on the board.
Food Grade Mineral Oil can be found at most drug stores near the laxative section.