Pat the hens dry using paper towels. Set the bird breast-side down on the counter and cut along one side of the spine with kitchen shears. The bones cut pretty easily. When you have cut from one end to the other, cut along the other side of the spine and remove the backbone.
Turn the bird over and flatten it with your hands. You might hear the breastbone crack, but that is completely normal.
Make the Dry Rub
Measure the dry rub ingredients and mix them in a bowl. The recipe yields 2/3 to 3/4 cup of BBQ rub. You will only need about 1/4 cup to season one Cornish hen, so scale the recipe based on how many hens you plan to grill.
Grill the Cornish Hen
Preheat the grill to 350°F on direct heat.
Grab the dry rub and liberally coat both sides of the bird. Don’t worry about brushing olive oil on first as the seasoning will adhere to the skin just fine, and the skin side is up at the beginning of the grill which will help keep the seasoning from falling off.
Place the hen over direct heat with the skin side up and grill for 15 minutes.
Turn the hen over and grill it skin side down for 15 more minutes.
The hen is fully cooked when the internal temperature of the thickest part reaches 165°F.
Remove from the grill and let rest for 10 minutes before serving.
Notes
Grill Multiple: Cornish hens are smaller than most chickens. It is just as easy to grill two, as it is to grill one, so it makes sense to throw a second one on the grill at the same time.Temperature Doneness: Make sure to check the temperature often. Spatchcocked fowl lay flat on the grill and will cook much faster than a traditionally prepared whole chicken.Sticking to Grill: It shouldn't stick but if you are worried, brush olive oil on the grill grates for safe measure.Storage: After the Cornish hen is cooled down, place it in an airtight container. It will last 3-4 days in the fridge.Substitutions: This recipe is a great "how to grill" vs using a certain rub or spice. Go crazy here and use which ones you love. Rosemary/thyme or garlic lovers: open up your spice cabinet and use some spice packets you received as gifts. The hen tastes just like chicken so gauge it like that.