3/4 cup evaporated milk
1 tablespoon unsalted butter
1 1/2 cups granulated sugar
2 cups mini marshmallows
2 tablespoons instant coffee crystals

Line a 13 x 9-inch pan with aluminum foil.

Stir all ingredients together in large glass bowl. Heat in microwave oven for 4 minutes, until it wells up. Take out and stir. Reheat 2 minutes more. Stir until marshmallows are dissolved. Immediately stir in:

12 ounces real semisweet chocolate chips
1/2 teaspoon vanilla extract
1 ounce chopped unsweetened chocolate (for rich fudge)
    and/or 2 tablespoons unsweetened cocoa powder (for drier fudge)

Stir well until all chocolate is dissolved. Pour fudge into prepared pan, spreading evenly. Let top dry overnight. Turn over on a board, peel off foil and let the bottom dry. Cut into pieces. Separate pieces and let them dry a bit more.

Pieces can be coated with melted coating chocolate, with a pecan or half a walnut on top.