Step by step

Method

4 steps

1. 1

   Line an 8-inch square pan with parchment, leaving overhang on two sides so you can lift the fudge out later.

2. 2

   In a large microwave-safe bowl, combine 3 cups (510 g) semisweet chocolate chips, one 14-oz can sweetened condensed milk, and 2 tablespoons butter. Microwave on high 1 minute, then stir hard from the center out. Continue in 20-second bursts, stirring after each, until the mixture is fully melted and looks thick, glossy, and uniform — usually 2–3 minutes total. If a few soft chips remain, the residual heat will finish them; don't keep blasting or the chocolate scorches.

3. 3

   Stir in 1 teaspoon vanilla and a pinch of salt. Fold in ½ cup chopped walnuts or mini marshmallows if you're using them. Scrape into the pan and spread into an even layer; tap the pan once on the counter to settle air bubbles.

4. 4

   Chill at least 2 hours until firm to the touch and the center doesn't leave a fingerprint. Lift out by the parchment and cut into 25–36 small squares with a sharp knife (wipe the blade between cuts for clean edges). Store in an airtight container in the fridge. You want dense, sliceable fudge that cuts clean — not a soft chocolate spread or a dry, crumbly brick.