Step 1

Prepare a 9-inch square baking pan by lining it with lightly greased parchment paper or non-stick aluminum foil.

Step 2

In a large, microwave-safe bowl place the chocolate chips and sweetened condensed milk. Microwave for 90 seconds at 70 percent power. Use the residual heat to stir the mixture well until the chocolate is fully melted and smooth. If necessary, microwave for additional 15 second intervals.

Step 3

If you prefer to cook on the stove-top instead of the microwave, melt the chocolate and milk in the top of a double boiler or in a bowl on top of a saucepan of simmering water.

Step 4

Remove from the heat and stir in the vanilla extract, nuts, and pinch of salt. Gently fold in the marshmallows.

Step 5

Pour and spread into the prepared pan. Chill until well set, several hours. Cut into squares.