My mom rarely uses recipes. If she does, it’s generally by Julia Child or the Joy of Cooking and then she opens up the cookbook but doesn’t really follow it. For this recipe, she started with Julia Child’s Standing Rib Roast recipe from her cookbook Julia Child & Company, which pretty much means she followed Julia’s instructions on when the meat was ready but little else. Here is my mom’s adaptation.
Mom’s Standing Rib Roast
Adapted from Julia Child & Company
Serves 4-6
Ingredients
1 10-pound rib roast (2 ribs in our case, but it could be 3 or 4 if you are working with a smaller cow)
2 tbsp. butter, room temperature
2 carrots, roughly chopped
1 medium onion, roughly chopped
2 cups water
Salt & pepper, for seasoning
Other Items Needed
Low-Sided Roasting Pan
Roasting Rack
Baster
Meat Thermometer
Directions
1. Take the meat out at least 1 hour before you plan to put it in the oven so it gets to room temperature. Trim the rib roast to remove the excess fat. Lightly season with salt & pepper – you don’t need much since the remaining fat will provide a lot of flavor for the meat.
2. Preheat oven to 325 degrees. Adjust rack position to lower level.
3. Smear the cut end of the beef with butter and place it fat side up (ribs down) on the rack in the roasting pan. Place carrots, onions and 2 cups water at the bottom of the roasting pan.
4. Place roast in oven. Every 30 minutes, baste the meat with the juices at the bottom of the pan and check the temperature of the meat in the thickest, middle section of the roast. If you want medium rare meat, take the roast out of the oven when the temperature reaches 125. This should take between 2 to 2.5 hours for the cut of meat.
5. When ready, remove roast from oven and cover with tinfoil to keep warm. Let sit for 15 minutes then carve.
6. Combine fresh grated horseradish with sour cream for garnish/extra flavor.
Sweet Southern Comfort 
This looks very good! I made something similar 4 years ago for the Christmas dinner. I like your version with those carrots and onions under the meat.