"My mom and I spent more than one Thanksgiving together, just the two of us. If we weren't out volunteering, we'd make a small, fancyish dinner." — Rachael Ray
Arrange a rack one notch above the center of the oven; preheat to 500°. Place a wire rack inside a rimmed baking sheet lined with foil for easy cleanup.
Using poultry or kitchen shears, remove the backbone from each hen by cutting along either side of it [1, above]; discard. Open the birds and turn skin-side up on a worksurface; press on the breastbone to flatten [2, above]. Drizzle with oil and season the birds with salt, pepper, the thyme, granulated onion, and granulated garlic. Place, skin-side up, on the prepared rack and into the oven. Reduce the temperatureto 475° and roast until an instant-read thermometer inserted into the thickest part of the thigh registers 165°, 20 to 22 minutes.
Meanwhile, place the potatoes in a medium saucepan, cover with water, and bring to a boil. Salt the water liberally and cook until tender, about 10 minutes. Drain and push the potatoes through a potato ricer back into the hot pot, or return to the pot and mash with a potato masher. Stir in the cheese, half-and-half, chives, horseradish, and butter; cover to keep warm.
In a large bowl, toss the cress, apple, and scallions with the lemon juice and EVOO.
Serve the birds on platters withthe potatoes and salad alongside.