To make fudge using condensed milk, combine 3 cups of semi-sweet chocolate chips with a 14-ounce can of sweetened condensed milk. Heat over low heat to melt the chips. Add 1 1/2 teaspoons of vanilla extract. Pour the fudge into a foil-lined, 9-inch square pan, and chill for 2 hours.
To make the fudge in the microwave, combine the ingredients in a microwave-safe container, and heat 1 1/2 minutes on high. Stir, and heat another 1 1/2 minutes. For fudge with nuts, stir in up to 1 cup of chopped nuts with the vanilla before pouring into the pan.
For a creamier fudge, stir in 2 cups of miniature marshmallows before melting the chocolate chips. For a lighter chocolate version, replace 1 cup of semi-sweet chocolate chips with 1 cup of milk-chocolate chips.
To adapt this recipe to a chocolate peanut butter chip glazed fudge, add 3/4 cup of peanut butter chips instead of the nuts. Then melt an additional 1/2 cup of peanut butter chips and combine with 1/2 cup of heavy cream for the glaze. Stir the glaze until it is thick and smooth. Pour the glaze over the chilled fudge and spread it evenly. Cut the fudge into 32 pieces and serve.