45-Day Duck Fat Aged Beef

  • By: Jack Mancuso

45-Day Duck Fat Aged Beef - Cuso Cuts

My 45-day duck fat-aged beef recipe comes out sublime. It’s good enough that I would swap the resulting steak for Wagyu any day. Prime rib is already tender and tasty, so the dry aging process serves to amp up the flavor profile.

The Dry Age Difference

I use a specialized temperature-controlled system that keeps humidity at consistent levels. For lack of a better word, the result is beefier. Sometimes you get subtle hints of butter or nuts. The texture is remarkably fork-tender. Aged beef takes “melt in your mouth” to a whole new dimension.Post Aging Prime Rib, ready to go!

Duck Fat, Ghee, Butter

The reason for using duck fat in this recipe is because it has a natural meaty taste. When you use it for making potatoes, for example, you’ll notice a distinct difference. By comparison, when you add it to a highly seasoned recipe, it’s hard to recognize the duck fat.

Ghee is clarified butter. Basically, you melt the butter until all the milk solids are removed. Ghee is clear, and for those with limited real estate in their refrigerator, Ghee can live in your panty just fine. It is the perfect vehicle for sauteing things like garlic and onions.

Factoid: When cooking with Ghee vs. Butter, remember Ghee does not burn as quickly, which comes in handy should you get distracted.

Of the three, butter has the lowest smoke point, which is why it’s not great for high-temperature preparations. Oven cooking is perfect for butter (which, of course, makes everything better).

45-Day Duck Fat Aged Beef Ingredients


  1. How much duck fat and ghee you need really depends on the size of your prime rib. The ratio of duck fat to ghee is 2 parts duck fat to 1 part ghee.
  2. Mix the fats together, adding about 2 tbs of our barbecue rubs.
  3. Smother all sides of the steak, and place it in the dryer.Beef coated with Ghee and Duck Fat
  4. After 45 days, remove the steak
  5. Using a Chef’s Knife, trim off all the exterior fat until the rib is clean.
  6. Slice into steaks
  7. Reverse sear the steaks
  8. Smoke them at 225 until the interior temperature reaches 110 F
  9. Let the steaks rest for 10 minutes before serving

PitMaster’s Memo

What is reverse searing? Rather than start your steak on the grill, you’re going to start in the oven and then transfer the steak to a grill or smoker. This is the best method for making a really beautiful crust. The steak cooks at a low temperature (225F), meaning it’s easier to monitor the meat’s temperature. The reward for your efforts is juiciness galore.


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