Preheat your oven to 400°F (200°C). Remove the Cornish hens from their packaging and pat them completely dry with paper towels. This is crucial for crispy skin!

In a small bowl, combine the softened butter, minced garlic, chopped rosemary, chopped thyme, salt, and pepper. Mix until well incorporated.

Carefully loosen the skin over the breast and thighs of each hen by gently sliding your fingers underneath. Spread about half of the herb butter mixture evenly under the skin of both hens.

Rub the remaining herb butter all over the outside of the hens.

Place the halved lemon and quartered onion inside the cavity of each hen. Add a few sprigs of fresh rosemary and thyme to the cavities as well.

Truss the legs of each hen together with kitchen twine, if desired (this helps them cook evenly and look neat).

Place the prepared hens in a roasting pan, breast-side up.

Roast for 50-65 minutes, or until the internal temperature reaches 165°F (74°C) in the thickest part of the thigh (avoiding the bone) and the juices run clear. Baste the hens with the pan juices halfway through cooking for extra moisture.

Once cooked, remove the hens from the oven and let them rest for 10-15 minutes before carving. This allows the juices to redistribute, ensuring a moist bird.