Prepare the Stuffing:

1. Sauté Vegetables: In a large skillet, melt the butter over medium heat. Add the chopped onion, celery, carrot, and garlic. Sauté for about 5 minutes until the vegetables are softened.
2. Add the Seasonings: Stir in the dried thyme, sage, salt, and pepper. Cook for another minute, allowing the herbs to release their aroma.
3. Combine with Bread and Broth: Remove from heat and add the cubed bread or breadcrumbs. Pour in the broth and toss until the bread is evenly moistened. Taste and adjust seasoning if needed. Set the stuffing aside to cool.

Prepare the Cornish Hens:

4. Preheat the Oven: Preheat the oven to 375°F (190°C).
5. Season the Hens: Rub the Cornish hens with olive oil, then season generously with salt and pepper inside and out. Stuff the cavity of each hen with the prepared stuffing mixture, packing it in gently.
6. Add Aromatics: Place the lemon halves and smashed garlic cloves inside each hen’s cavity along with some fresh herbs. These will infuse the meat with wonderful flavor as it roasts.

Roast the Cornish Hens:

7. Place in the Oven: Arrange the stuffed Cornish hens on a roasting rack or a baking sheet. Roast them in the preheated oven for 60-70 minutes, or until the internal temperature reaches 165°F (75°C) when measured at the thickest part of the bird, and the skin is golden and crispy.
8. Baste (Optional): Halfway through cooking, you can baste the hens with some of the pan drippings to keep them moist and enhance the flavor.

Serve the Cornish Hens:

9. Rest the Hens: Once the Cornish hens are fully cooked, remove them from the oven and let them rest for about 10 minutes. This helps the juices redistribute and makes carving easier.
10. Carve and Serve: Serve each Cornish hen on a plate with the stuffing. You can garnish with extra fresh herbs or a wedge of lemon for an added burst of citrus flavor.