Slow-Roasted Prime Rib with Rosemary and Dijon Crust

By AislePrompt Test Kitchen · Reviewed by AislePrompt Editorial · ·

Prime rib slowly roasted with a fragrant rosemary and Dijon mustard crust, yielding a tender interior and flavorful crust perfect for festive dinners. This american-inspired christmas ready in about 225 minutes pairs prime rib roast, Dijon mustard, fresh rosemary, chopped for a weeknight-friendly dinner that comes together with one pan and minimal cleanup. Each serving lands at about 620 calories and feeds 6, so it slots cleanly into a weekly meal plan and pairs well with a quick salad or grain on the side. Tap "Plan a meal with the AI" below to drop this recipe into your week and send the ingredients straight to Instacart.

★ 4.6 (12 ratings) Prep: 15 min Cook: 210 min Serves 6 American cuisine 620 cal/serving
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Ingredients

Instructions

  1. Step 1: Preheat oven to 250°F. In a small bowl, mix 1/4 cup Dijon mustard, 3 tablespoons chopped fresh rosemary, and 4 minced garlic cloves until combined.
  2. Step 2: Pat dry 5 lbs prime rib roast with paper towels, then rub all over with 1 tablespoon kosher salt, 1 tablespoon black pepper, and 2 tablespoons olive oil.
  3. Step 3: Spread the Dijon-rosemary mixture evenly over the entire roast, pressing gently to adhere.
  4. Step 4: Place roast on a rack in a roasting pan and insert an oven-safe meat thermometer into the thickest part.
  5. Step 5: Roast in the preheated oven for 3 to 3 1/2 hours, or until the internal temperature reaches 125°F for medium rare.
  6. Step 6: Increase oven temperature to 500°F and roast for an additional 10 minutes to develop a crust.
  7. Step 7: Remove roast from oven and tent with foil; let rest for 20 minutes before slicing thinly against the grain and serving.

Frequently asked questions

How long does Slow-Roasted Prime Rib with Rosemary and Dijon Crust take to make?

Total time is about 225 minutes (15 min prep + 210 min cook). Most home cooks find this fits comfortably into a weeknight; double the batch on Sunday for two dinners.

How do I store leftover Slow-Roasted Prime Rib with Rosemary and Dijon Crust?

Cool to room temperature within 2 hours, then store in an airtight container in the fridge for up to 4 days. Reheat covered in a 350°F oven for 10-12 minutes, or microwave at 70% power in 60-second bursts to keep prime rib roast from drying out.

Can I substitute ingredients in Slow-Roasted Prime Rib with Rosemary and Dijon Crust?

Yes — most ingredients in this recipe have flexible swaps. For oil, use any neutral high-smoke-point oil (avocado, grapeseed, refined coconut). For aromatics, dried herbs at ⅓ the volume of fresh work in a pinch. The full ingredient list is shoppable on Instacart so you can see substitutes in real time.

How do I scale Slow-Roasted Prime Rib with Rosemary and Dijon Crust for a different number of people?

The recipe is written for 6 servings. Multiply each ingredient by (your serving target / 6). Cook time stays roughly the same up to 2x; for 3-4x batches, switch from a skillet to a sheet pan or stockpot so the food isn't crowded — overcrowding steams instead of browns.

What goes well with Slow-Roasted Prime Rib with Rosemary and Dijon Crust?

American christmas like this pair well with a simple grain (rice, couscous, or crusty bread), a quick salad with acid (lemon vinaigrette, pickled onions), and a pan sauce or yogurt-based dip. Tap "Plan a meal with the AI" to get specific side suggestions.

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