Prepare the pan: Line your 8x8-inch baking pan with parchment paper and lightly butter the sides.
Melt the base: In a medium saucepan, combine sugar, evaporated milk, and butter. Bring to a gentle boil over medium heat, stirring constantly for about 4-5 minutes until the mixture thickens slightly.
Add the chocolate: Remove from heat and immediately stir in chocolate chips. Mix until completely melted and smooth.
Add Jet-Puffed marshmallows: Stir in Jet-Puffed marshmallow creme (or mini marshmallows) and vanilla extract. Keep stirring until everything is fully combined and glossy.
Pour and set: Pour the fudge into your prepared pan, smoothing the top with a spatula. Optional: sprinkle chopped nuts or sea salt on top.
Cool completely: Let it cool at room temperature for about 2 hours (or refrigerate for 1 hour for faster setting).
Slice and serve: Cut into bite-sized squares and enjoy with a cozy drink like Dalgona Coffee Recipe. Store leftovers in an airtight container.