Line baking pan with foil for later. 

Add to saucepan:

   - 1 1/2 cups granulated sugar

   - 5 oz (2/3 cup) evaporated milk

   - 2 Tbs butter

   - 1/4 tsp salt

While constantly stirring, bring to a full rolling boil for 4-5 minutes.

Turn off heat and add, in order:

   - 1 1/2 cups baking chips

   - 4 oz marshmallows

   - 1 tsp vanilla

Stir until marshmallows are melted and pour into baking pan. Refrigerate until firm.