The scenario goes, suddenly in the mood for roast beef sandwiches; oh no!, all you have is a frozen solid roast in the freezer. What to do? Defrost in the microwave? Hate that, as it eventually begins cooking if you don't time it correctly. Defrost in the refrigerator? Then it won't be ready for roasting until tomorrow....you want it today! Calm down, you can have that roast beef ready in the same amount of time as if it was defrosted; just as tender and juicy as you like it too. Impossible?
Not if you use heavy duty aluminum foil, or one of those aluminum grill bags; roasting in the foil will help keep the moisture in, while maximizing the heat needed to have the beef cooked to the desired doneness in the correct amount of time. I took a frozen solid, three pound rump roast and seasoned it all around with a mixture of: 1 teaspoon each of onion and garlic powders, 1 teaspoon crushed, dried thyme, 1/2 tsp ground black pepper and 1/4 teaspoon of fine sea salt. Placing it inside my aluminum foil pouch, I then surrounded it with an entire tray of ice cubes. Why the ice cubes? To create steam that would not just help the roast defrost properly, but mix with any beef juices that escaped to create an au jus; or a gravy if combined with a cornstarch slurry.
Preheating the oven to 350F; I sealed all the sides tightly to make sure no steam or liquid would leak out. I placed the package on top of a rack inside a roasting pan; again, if there was any leakage of liquid, the pan would catch it. After two hours I placed a food thermometer into the package at its thickest part which was easy to make out through the bump in the foil package. Now be careful when doing this that you don't push it in too far and puncture the bottom; you'll lose that liquid into the pan. At 2 1/2 hours, it was at rare; at 2 3/4 hours it was at medium; we usually enjoy medium-rare, so I was amazed at how it jumped from rare to medium within a 15 minute time period.
Carefully opening the top of the bag with the point of a knife, the steam escaped completely and left me with a fully cooked roast with a crisp seasoned coating; in the same amount of time as if it had been defrosted first. I removed the beef to a cutting board to rest before slicing. Inside the bag was a lovely brown liquid that I could serve over the roast as is, or as I mentioned earlier, make a cornstarch slurry and create a gravy with. Of course I strained the liquid before using it.
The beef was a medium doneness, tender, juicy, wonderfully seasoned; the scent of the garlic and onion was entralling. My sharp knife cut through it like it was butter; and I just couldn't keep a piece from jumping into my mouth now and then.
So don't panic next time you want to make a roast, but it's frozen solid and you're worried over time. Using heavy duty aluminum foil will get you done on time and with the same results.