This is the best fudge EVER! I love creamy fudge, but didn't want to mess with a candy thermometer or risk an error. This recipe is foolproof! It is my own creation after combining the best ideas from several recipes.
Lightly spray 8x8 inch pan with vegetable cooking spray or line pan with parchment.
Combine all ingredients except vanilla in a heavy saucepan and melt over low heat, stirring constantly.
Remove from heat. Stir in pure vanilla extract. Pour into prepared pan. Quickly smooth top with offset spatula. Chill in refrigerator until firm. Don't cover the fudge until it is cool to avoid condensation. Let fudge come back to room temperature for easier cutting.
Variation: Use 11-12 ounces semisweet chocolate and 6-7 ounces milk chocolate. In fact, any combination of chips would work. Be creative! I usually make the chocolate version, but you could try white chocolate, butterscotch, mint, etc. Different combinations of chips and chopped or crushed candy, nuts, dried fruit, etc. can be added. The type of chips used influences the firmness of the fudge. Semisweet or dark chocolate chips make the firmest fudge. White chocolate chips or butterscotch chips make a softer fudge. The amount of marshmallows used will influence the firmness of the fudge...the more marshmallows, the softer the fudge. This recipe is also delicious with melted blocks of high quality chocolate. Store fudge in a tin on the counter or in the refrigerator.