U S Navy SOS.

Dice half of a med onion, add to a pound of 80/20 ground chuck.  Cook until brown in heavy skillet.  Add 2 tbs flour, stir to be absorbed by meat.  Add 1/2 stick butter, stir.  Add 2 cups milk a little at a time, constantly stirring.  Add salt, pepper to taste.  Now add about 1/2 tsp of nutmeg, stir more.

Serve over toasted bread, or if you prefer, hot biscuits.