Step 1: Prepare the Prime Rib
Remove the roast from the refrigerator about 2 hours before cooking so it reaches room temperature.
Step 2: Season
Rub the roast with olive oil, then coat evenly with salt, pepper, garlic powder, onion powder, rosemary, and thyme.
Step 3: Roast
Preheat the oven to 500°F (260°C).
Roast for 20 minutes to develop a flavorful crust.
Reduce the oven temperature to 325°F (163°C) and continue roasting until the internal temperature reaches:
- 120–125°F (49–52°C) for Rare
- 130–135°F (54–57°C) for Medium-Rare
- 140°F (60°C) for Medium
Step 4: Rest
Remove the roast from the oven and let it rest for 20–30 minutes before slicing.
Step 5: Make the Mashed Potatoes
Boil the potatoes until fork tender, about 15–20 minutes.
Drain well, then mash with butter and heavy cream until smooth. Season with salt and pepper.
Step 6: Prepare the Creamed Spinach
Melt butter in a skillet over medium heat.
Cook the garlic for about 30 seconds, then add the spinach and cook until wilted.
Stir in the heavy cream and Parmesan cheese. Simmer for 2–3 minutes until creamy. Season with salt and pepper.
Step 7: Make the Gravy
Melt butter in a saucepan and whisk in the flour.
Cook for 1 minute, then slowly whisk in the beef drippings or broth.
Simmer until thickened, about 5 minutes. Season to taste.
Step 8: Serve
Slice the prime rib against the grain and serve with creamy mashed potatoes, rich gravy, and creamed spinach.
Prep Time: 20 minutes (+2 hours resting before cooking)
Cook Time: 2–2½ hours
Rest Time: 20–30 minutes
Total Time: About 5 hours (including bringing meat to room temperature)
Servings: 6–8
