cooking / desserts

Fantasy Fudge (Jet-Puffed Marshmallow)

serves about 70 pieces (fills a 13x9 pan) · 2.5-4.5 hours · 10 minutes hands on · medium

Why This Works

Classic marshmallow-creme fudge depends on hitting soft-ball stage, and soft-ball stage moves with altitude. Water boils around 202°F at 5,280 feet instead of 212°F, so the target temperature drops about 2°F per 1,000 feet — pull the fudge at 224°F at Denver altitude instead of the sea-level 234°F, and a candy thermometer becomes essential.

Ingredients

  • Granulated sugar (3 cups)
  • Salted butter (3/4 cup / 1.5 sticks, room temperature, cubed)
  • Evaporated milk (1 can, 5 oz, room temperature)
  • Semi-sweet chocolate chips (1 bag, 12 oz, room temperature)
  • Marshmallow creme (1 jar, 7 oz, Jet-Puffed)
  • Vanilla extract (1 tsp)
  • Chopped walnuts (1 cup, optional)

Equipment: 13x9 baking pan, parchment paper, heavy-bottomed saucepan, candy thermometer (essential at altitude), spatula, timer.

Method

  1. Prepare the pan. Line a 13x9 pan with parchment paper, leaving overhang for easy removal.
  2. Measure everything first. Have all ingredients measured and near the stove — this moves fast once boiling starts.
  3. Cook the base. Combine sugar, butter cubes, and evaporated milk in a heavy-bottomed saucepan. Heat over medium, stirring constantly as the butter melts and sugar dissolves. Bring to a rolling boil. At altitude (5,280 ft): cook to 224°F (sea level: 234°F) — roughly 4-4.5 minutes of boiling at altitude (5 minutes at sea level). Remove from heat immediately when the temperature is reached.
  4. Add remaining ingredients. Add the chocolate chips and stir until completely melted. Stir in the marshmallow creme and vanilla, beating until combined. Fold in walnuts if using.
  5. Pour and chill. Pour into the prepared pan and smooth the top with a spatula. Cool completely at room temperature, then refrigerate until firm (2-4 hours). Cut into 1-inch squares.

Notes

Altitude adjustment (tested at 5,280 ft):

  • Water boils at ~202°F at this altitude instead of 212°F
  • Pull the fudge at 224°F instead of 234°F (soft-ball stage adjusted)
  • Subtract ~2°F per 1,000 feet of elevation
  • Temperature is more reliable than timing at altitude — use the thermometer

Critical success factors: all ingredients at room temperature for even cooking; stir constantly to prevent scorching; medium heat, not high — don't rush it.

Storage: 2 weeks at room temperature in an airtight container, 1 month refrigerated, up to 4 months frozen. Texture is best at room temperature — the fridge makes it harder.

A classic Christmas candy: cut into cubes and stack on a plate.