Costco vs. Sam's Club Cooking Challenge

Ingredients

• 10 lb Prime Rib Roast (Trimmed, room temperature before cooking)
• 0.25 cup Kosher Salt (For crust; can be applied the night before)
• 2 tbsp Dijon Mustard (Mixed into butter for a mustard butter rub)
• 1 cup Unsalted Butter (Softened; divided for roast, potatoes, spinach, and lobster)
• 8 cloves Garlic Cloves (Minced; used in mustard butter, spinach, and lobster butter)
• 5 lb Yukon Gold Potatoes (Boiled whole, then riced)
• 1.5 cup Heavy Cream (Divided between mashed potatoes and creamed spinach)
• 0.5 cup Whole Milk (Adjusts mashed potato consistency)
• 4 oz Philadelphia Cream Cheese (Adds richness to mashed potatoes and spinach)
• 0.5 cup Parmesan Cheese (Grated; folded into mashed potatoes)
• 1 lb Fresh Spinach (Washed and trimmed; used for creamed spinach)
• 1 medium Yellow Onion (Diced for spinach base)
• 5 lb Lobster Tails (Thawed; split and brushed with garlic butter)
• 1 whole Lemon (Cut into wedges for serving)
• 0.25 cup Fresh Parsley (Chopped; garnish for lobster and roast)
• to taste Black Pepper (Freshly cracked)

Instructions

1. Trim and Portion the Roast

   Using kitchen shears, trim excess fat and silver skin from the 10‑lb prime rib roast, then cut it into two pieces (approximately 8 lb and 2 lb) to match the Sam's Club size.

   Time: PT15M

2. Apply a Salt Crust

   Generously coat the entire surface of each roast piece with kosher salt, creating a thick white crust. Let sit at room temperature for 10 minutes.

   Time: PT10M

3. Make Mustard‑Butter Rub

   In a mixing bowl, combine softened unsalted butter, Dijon mustard, and minced garlic until smooth.

   Time: PT5M

4. Rub the Roast

   Pat the mustard‑butter mixture onto the salted roast, ensuring an even coating on all sides.

   Time: PT5M

5. Preheat Oven for Low‑Temp Roast

   Set the oven to 225°F (107°C) and allow it to preheat.

   Time: PT10M

   Temperature: 225°F

6. Low‑Temp Roast

   Place the roast on a rack in a roasting pan and roast until the internal temperature reaches 115°F (46°C) for rare or 118°F (48°C) for medium‑rare, about 3 hours.

   Time: PT3H

   Temperature: 225°F

7. Reverse Sear (High‑Heat Blast)

   Increase oven temperature to 500°F (260°C) and roast for an additional 15 minutes, or until a deep brown crust forms.

   Time: PT15M

   Temperature: 500°F

8. Rest the Roast

   Remove the roast from the oven, tent loosely with foil, and let rest for 20 minutes before carving.

   Time: PT20M

9. Boil Potatoes

   Place the Yukon Gold potatoes in a large pot, cover with cold salted water, and bring to a boil. Cook until fork‑tender, about 15‑20 minutes.

   Time: PT20M

   Temperature: 212°F

10. Rice Potatoes

    Drain potatoes and run them through a potato ricer into a warm mixing bowl.

    Time: PT5M

11. Finish Mashed Potatoes

    Add the softened butter, heavy cream, milk, cream cheese, and grated Parmesan to the riced potatoes. Stir over low heat until smooth and creamy; season with salt and pepper.

    Time: PT10M

    Temperature: Low heat

12. Keep Mashed Potatoes Warm

    Transfer mashed potatoes to a covered dish and keep in a warm oven (200°F) or on a low‑heat stovetop until ready to serve.

    Time: PT5M

    Temperature: 200°F

13. Sauté Onion and Garlic for Spinach

    In a saucepan, melt 2 tbsp butter over medium heat. Add diced onion and minced garlic; sauté until translucent, about 5‑7 minutes.

    Time: PT7M

    Temperature: Medium heat

14. Cook Spinach

    Add fresh spinach to the saucepan, stirring until wilted, about 3‑4 minutes.

    Time: PT4M

    Temperature: Medium heat

15. Cream the Spinach

    Stir in heavy cream, cream cheese, and a pinch of salt and pepper. Simmer gently for 3‑5 minutes until thickened.

    Time: PT5M

    Temperature: Low heat

16. Prepare Lobster Tails

    Using kitchen shears, cut down the top of each lobster shell lengthwise, then gently lift the meat out, keeping it attached at the base. Set shells aside for presentation.

    Time: PT10M

17. Make Garlic Butter for Lobster

    Melt 4 tbsp butter in a small pan, add minced garlic, and cook 1‑2 minutes until fragrant. Brush generously over lobster meat.

    Time: PT5M

    Temperature: Low heat

18. Broil Lobster Tails

    Place lobster shells on a baking sheet and broil on high for 4‑5 minutes, until the meat is opaque and lightly browned.

    Time: PT5M

    Temperature: High broil

19. Carve and Plate

    Slice the rested prime rib into 1‑inch thick slices. Plate each serving with a mound of mashed potatoes, a spoonful of creamed spinach, and a broiled lobster tail. Garnish with chopped parsley and a lemon wedge.

    Time: PT15M

Nutrition Facts

Calories

920

Protein

62 g

Carbohydrates

48 g

Fat

58 g

Fiber

5 g