Some good recipes for fudge using condensed milk include Ultimate Fudge, Foolproof Chocolate Fudge and Butter Fudge. Another good recipe, Microwave Fudge, calls for only four ingredients. Melt semisweet chocolate chips in a microwave, stir in 1 can of sweetened condensed milk, and add nuts and 1 teaspoon of vanilla.
Make Ultimate Fudge by combining 2/3 cup of milk, 1 can of condensed milk, 16 ounces of demerara sugar and 4 ounces of butter in a saucepan. Stir everything together, and cook over low heat until the sugar dissolves. Then bring the mixture to a boil, reduce the temperature and simmer for 10 to 15 minutes. Stir constantly so that the mixture doesn't stick to the pan and burn. Once the fudge reaches 244 degrees Fahrenheit with a sugar thermometer, remove from heat, and beat for 10 minutes. Press the fudge into a baking pan, and allow to set completely and cool before serving.
To make Foolproof Chocolate Fudge, pour 3 cups of semi-sweet chocolate chips and 1 14-ounce can of sweetened condensed milk into a saucepan with 1 dash of salt. Heat on low until the chocolate melts. Remove the pan from the stove, and stir in 1 1/2 teaspoons of vanilla extract. You can also choose to add 1/2 to 1 cup of chopped nuts. Pour the fudge into a rimmed pan, and refrigerate for two hours.