Pour the buttermilk into a large bowl or container with a lid. Place the hens in the buttermilk. Cover, and refrigerate overnight.

When you are ready to cook, prepare a baking sheet with parchment paper or aluminum foil (to avoid mess) and place a baking rack inside of the baking sheet. The layers will go baking sheet, parchment, rack. Preheat the oven to 425F.

Remove the hens from the buttermilk (let excess drip away and discard all of the buttermilk) and sprinkle them all over liberally with kosher salt. Place breast side up on the prepared baking rack.

Roast the Cornish game hens uncovered for 1 hour until the skin is dark and crispy. Let rest for 10 minutes before serving.

I cut the hens in half down the spine for serving, but you can remove the meat from the bones for easier eating, or portion 1 hen per person for larger portions and leftovers.