Foolproof Old-Fashioned Chocolate Fudge

Prepare your pan. Line an 8x8 or 9x9-inch baking pan with parchment paper, leaving an overhang on two sides to easily lift the fudge out later. Lightly grease the parchment and any exposed sides of the pan.

Combine the melting ingredients. In a large heatproof bowl, combine the semi-sweet chocolate chips, marshmallow creme, and chopped unsweetened chocolate. Set this bowl aside near your stove.

Start the candy base. In a 3-quart heavy-bottomed saucepan, combine the granulated sugar, cubed butter, evaporated milk, and fine sea salt. Place over medium heat.

Stir and dissolve. Stir the mixture constantly with a wooden spoon or heatproof spatula until the butter is melted and the sugar has completely dissolved. This will prevent a grainy texture.

Bring to a boil. Increase the heat to medium-high and bring the mixture to a full rolling boil, stirring constantly. Once boiling, attach a candy thermometer to the side of the pan, making sure the tip is submerged but not touching the bottom.

Cook to soft-ball stage. Continue boiling and stirring constantly until the thermometer registers exactly 234°F (soft-ball stage). This should take about 5-8 minutes. Constant stirring is crucial to prevent scorching.

Combine all ingredients. Immediately remove the saucepan from the heat. Carefully pour the hot sugar mixture over the chocolate and marshmallow creme in your prepared bowl. Add the pure vanilla extract.

Beat the fudge. Beat the mixture vigorously with a wooden spoon until the chocolate is fully melted, the ingredients are well combined, and the fudge just begins to lose its glossy sheen. This should take about 1-2 minutes. Do not overmix.

Add nuts and set. Quickly fold in the chopped nuts. Immediately pour and spread the fudge evenly into your prepared pan using a spatula.

Cool completely. Let the fudge cool on a wire rack at room temperature for at least 4 hours, or overnight, until completely firm. Do not refrigerate it to speed up the process, as this can affect the texture.

Cut and serve. Once firm, use the parchment paper overhangs to lift the fudge from the pan onto a cutting board. Cut into small squares and serve.