Make fudge in the microwave by combining three cups of semi sweet chocolate chips, one 14 ounce can of sweetened condensed milk, 1/4 cup softened butter, and 1 tablespoon of vanilla in a microwave safe bowl. Heat at 50% power, stopping to stir every 30 seconds, until the mixture is completely melted. Pour into a lined baking pan and chill for 2-3 hours.