1 can sweetened condensed milk
3 cups chocolate chips (semi-sweet or milk chocolate - cook's choice)
Chocolate chips can be melted in either microwave or double boiler (if double boiler is used add sweetened milk after chips melt...if microwaved, also add sweetened milk and stir the 2 ingredients often ).
When mixture is creamy smooth, quickly spread into foil lined 9x9 pan sprayed with a tad of non-stick spray. Refrigerate until firm, turn out onto cutting board and remove foil. Cut into squares of desired size (I use a wooden ruler to measure/score 1" squares before cutting with knife long enough to reach across entire batch of fudge).
Chopped pecans, peanut butter, shredded coconut, etc. can be added if desired.