Question: how to cook frozen fully cooked sausage?
Answer: If you mean cooking them straight from a frozen state, place the sausages in a pan of water. Water should go about 1/3 to 1/2 of the way up the side of the sausages. Turn flame on medium-high and once the water starts to boil lower it to a simmer and cover the pan with a lid. Just cook until sausages are thawed.