Prep Time: 50 min.
Preheat the oven to 450 degrees Fahrenheit.
Rinse the bird and pat dry. Whip together butter, the juice and zest from half the lemon, and 1 tablespoon chopped rosemary. Lift the skin at the neck of the bird and use your fingers to gently create space between the skin and the muscle, then use your fingers to rub the butter mixture into the muscle for as much of the bird as you can reach. Place a whole sprig of rosemary and a wedge of lemon within the cavity of the bird. Place the bird in a baking dish and roast in the preheated oven for 35-45 minutes, basting every 10 minutes with the juices collecting in the pan, until the outside is browned and the muscle is cooked through but not dried out.
While the hen is roasting, cube rutabaga and rinse under cold water until the water runs clear. Rinsing the starch off will allow the cubes to become crispy. Pat dry, then toss with olive oil, salt and pepper in a large bowl. Spread the cubes on a baking dish and roast in the oven with the hen is roasting until crispy on the outside and soft in the middle, about 20-30 minutes.
Heat olive oil over medium high heat in a skillet. Add tomatoes and sautée until they’re blistered, about 5 minutes, then add kale, salt and pepper, and cook until kale has slightly softened, about 3 minutes. Squeeze the remainder of the lemon over the vegetables. Cover and set aside.Once the cornish hen is done roasting, remove from the pan, place on a cutting board and allow to rest for 5 minutes before carving. Transfer cooking liquids to a skillet, and simmer until it’s slightly thickened. Season with salt and pepper to taste. Use it as sauce over the rutabaga and cornish hen when serving.