• With a pair of kitchen shears, cut along both sides of the back bone of each hen. Remove and discard the backbone. Turn the hen over, splayed out flat with the skin side up. With your hands, apply pressure directly to the top of the breast, flattening the hen as much as possible. With a sharp knife, cut the hen in half, directly through the center of the breast bone.
• Slip your fingers between the skin and flesh of the legs and the breast, loosening the skin. Using a skewer or ice pick, prick both the legs and breast area to allow the fat to flow out as it cooks.
• With paper towels, pat both sides of the hens dry. In a small dish, mix the salt and rosemary together, turn the hens boney side up and sprinkle with half of the salt-rosemary mix, then turn the wing tips under.
• To the remaining salt-rosemary mix add the oil and mix together thoroughly. Add the baking powder and mix well to combine. Rub the mixture on the skin side of the game hens, transfer them to a sheet pan and refrigerate to dry out for at least 4 hours, preferably overnight.

When ready to roast the cornish game hens:

• Preheat the oven to 500°F and place a baking sheet in the oven for 15 minutes to heat.
• Remove the game hens from the refrigerator and brush lightly with vegetable cooking oil and sprinkle with black pepper. Add the game hens, oiled skin side down, onto the piping-hot baking sheet. Transfer the baking sheet to the oven and roast for 15 minutes. Remove them from the oven and immediately turn the oven to BROIL.
• Flip the game hens over, skin side up, and return the baking sheet to the oven and broil them for 5 minutes more to a crispy, golden brown and they register 160°F on an instant read thermometer.
• Serve immediately.