To make microwave fudge, combine 1/2 cup butter, 1/4 cup milk and 1 cup semi-sweet chocolate chips in a bowl and microwave for two to three minutes. Stir in 3 cups powdered sugar and 1 teaspoon vanilla and mix until smooth. Pour into a lined pan and refrigerate until firm.
Use an 8-by-8 inch baking pan for the fudge mixture. Line it with aluminum foil that extends out over the edges. Butter the foil before pouring the fudge mixture in. Refrigerate for about 60 to 90 minutes, until the fudge is fully firm. Use the edges of the foil to lift the fudge out of the pan and cut it into squares before serving.
If you want fudge with nuts, simply stir in about a 1/2 cup or so.
You can make a number of fudge varieties in the microwave. To make a sea salt white chocolate fudge, combine 2 cups of white chocolate chips, 1 14-ounce can of condensed milk and 3 tablespoons of butter in a microwave-safe bowl. Microwave until the chocolate and butter fully melts. White chocolate can be very temperamental, so microwave the mixture in 30-second intervals, stirring in between.
Pour the mixture into the prepared pan and chill in the refrigerator until set. Sprinkle the fudge with coarse sea salt before cutting it into squares.