Happy Mother's Day Just Like Nana's Fudge

Adapted from the New York Times, adapted from Michael Chu's Cooking for Engineers
4 tablespoons butter, plus extra for greasing the pan
1 pound (3 cups) good quality semisweet or bittersweet chocolate chips
1 (14-ounce) can sweetened condensed milk
1/8 teaspoon salt (optional)
1/2 cup chopped, toasted nuts or dried fruit of your choice (optional)

Grease an 8x8-inch square baking pan and line with two overlapping pieces of parchment or waxed paper.  Paper should at least come up to the top of pan to later serve as handles.
Combine butter, chocolate, milk and salt in double boiler or pan set over simmering water OR place all ingredients in microwave safe bowl and nuke on medium for 20 second intervals, stirring between nukes.  Either technique, heat just until completely melted.  You don’t want the mixture to get too hot.
Scrape mixture into prepared pan and smooth with spatula. Refrigerate until set. At least 4 hours or overnight.
Lift fudge on paper out of pan and use a large knife (a ruler is helpful too) to cut into one inch squares. If fudge is too stiff to cut, let it sit on counter to soften a bit.

NOTE1: Fudge tastes even better when left to ripen a day or so in an airtight container

Yield: 49 one-inch squares.

NOTE 2:  If you are someone who likes to shake-up your fudge with nuts or dried fruit, stir in ½ cup of your favorite to the mixture after melting but before scraping into prepared pan.