Quick defrost one pound chopped beef

It's actually faster and just as safe to have cool water continually running over the sealed meat. It's how we do it in restaurants.

Here's what the USDA says:

To defrost ground beef more rapidly, you can defrost in the microwave oven or in cold water. If using the microwave, cook the ground beef immediately because some areas may begin to cook during the defrosting. To defrost in cold water, put the meat in a watertight plastic bag and submerge. Change the water every 30 minutes. Cook immediately. Do not refreeze raw ground meat thawed in cold water or in the microwave oven unless you cook it first.

Never leave ground beef or any perishable food out at room temperature for more than 2 hours (1 hour at 90 °F and above).