how long to cook frozen 2 lb beef roast
for a 2 1/2 lb roast beef: Preheat your oven to high 400-425. put frozen roast in for 15-25min. Searing this way on the outside will seal in juices. Reduce the heat to 300 and cook abt..2 more hours. I try to cook all my roasts frozen because I prefer my meat to be rare. you may wish to cook yours longer.our roast should be covered wi â¦ th foil for the first half of the roasting time to prevent drying the outer layer. 3 to 5lb Joint 1Â½ to 2 hours 5 to 7 lb Joint 2 to 2Â½ hours 7 to 10lb Joint 2Â½ to 3 hours The beef can be taken out sooner if you prefer rare (bloody) meat. Tips for a better roast.