Prep the hens. First, remove any giblets from the cavity of the cornish game hens and make sure they’re completely defrosted (if using frozen hens). Place them on a large cutting board and pat them very dry with paper towels, inside and out. Place them on a parchment lined baking sheet and liberally season all over (front and back and inside) with kosher salt and black pepper (about 2 teaspoons salt per bird) and really rub it into the skin of each bird. Transfer uncovered to the fridge for 8 hours.
Remove hens from the fridge 1 hour before you plan to cook.
Make the glaze. Combine the butter, maple syrup, dijon, and herbs in a small saucepan. Simmer over medium-low heat until the mixture is thick enough to coat the back of a spoon, about 10 minutes. Stir in the pepper and cool slightly.
Preheat an oven to 400 F.
Stuff the hens. Stuff the cavity of each hen with 2-3 cloves of garlic, 1/2 a shallot, and 2 sprigs of thyme. Tuck the wings behind the breasts and use a piece of kitchen twine to truss the legs together. Drizzle with the olive oil and work it into the skin. Place the hens in a roasting pan or braiser.
Roast and baste the hens. Place the hens in the oven. After the first 25 minutes, baste the hens with the glaze every 5 minutes or so. The hens are done when the thickest part of meat not touching bone registers at 165 F, about 55-65 minutes total cooking. Let the hens rest for 15-20 minutes before serving.
You can use the drippings to make my foolproof gravy.