In the cavity of each Cornish game hen, add 1 cup of prepared stuffing. Place hens, breast side up, in the UltraPro 2-Qt./2 L Square Pan (or UltraPro 2-Qt./2L Casserole Pan). Rub each hen with butter. Add carrots, parsnips and mushrooms to pan. Sprinkle vegetables and hens with salt and pepper.
Cook the game hens
Place pan in microwave. Microwave on high power 12 minutes. Remove pan from microwave. Baste vegetables and hens with pan drippings. Place pan in oven. Bake an additional 20 minutes or until hens are golden brown and register 160° F/72° C on an instant-read thermometer inserted into the middle of the stuffing.
Assemble, plate and serve
Remove pan from oven and let stand 5 minutes. Transfer hens to a cutting board. Cut hens in half lengthwise.
