Peanut Butter Fudge Recipe Using Marshmallow Fluff: Decadent No-Bake Squares

This no-bake fudge delivers rich peanut butter flavor with minimal effort. The marshmallow fluff creates an ultra-creamy texture that melts in your mouth.

No oven required—just melt, mix, and chill. The combination of peanut butter, sugar, and fluff creates a smooth, decadent base that sets into perfect squares.

After 10 minutes of prep and 2 hours in the fridge, you’ll have a batch of fudge that’s impossible to resist. Each piece is dense, sweet, and packed with peanut butter goodness.

Ideal for gifting or satisfying a sweet tooth. This recipe proves that the best treats don’t need heat.

Ingredients for Peanut Butter Fudge Recipe Using Marshmallow Fluff

Seven simple ingredients create these melt-in-your-mouth no-bake squares with rich peanut butter flavor.

The peanut butter is the star here. Jif or Skippy creamy works perfectly—avoid the natural stuff that separates (it won’t blend as smoothly). Marshmallow Fluff brand is what you want—it’s in the baking aisle near the marshmallows. Most grocery stores carry it, but if you’re at Walmart or Target, you’ll find it easily. The butter should be real, unsalted so you control the salt level.

No marshmallow fluff? Jet-Puffed marshmallows melted with a splash of milk works in a pinch (about 2 cups marshmallows). Swap granulated sugar for brown sugar if you want a deeper caramel note. Using natural peanut butter? Stir it really well first and add 1 extra tablespoon of butter to compensate for the oil. The vanilla can be imitation if that’s what you have, but pure tastes better.

This keeps beautifully at room temp in an airtight container for up to 1 week. For longer storage, pop it in the fridge for 2-3 weeks. Cut into squares once fully set, then layer between parchment paper to prevent sticking.

Step-by-Step Instructions for Peanut Butter Fudge Using Marshmallow Fluff

No oven required—this simple method delivers creamy, melt-in-your-mouth fudge every time.

Step 1: Combine and Melt the Base Ingredients

In a large, heavy-bottomed saucepan, combine the 2 cups Granulated Sugar, 1.5 cups Creamy Peanut Butter, and 0.5 cup Unsalted Butter. Place the pan over medium heat and stir constantly with a wooden spoon.

As the mixture warms, the butter will melt first, followed by the sugar dissolving. Keep stirring until everything is completely smooth and you can no longer see any sugar granules. This should take about 5-7 minutes.

Watch for the mixture to start bubbling gently around the edges—that’s your cue it’s ready for the next step. Don’t let it reach a rolling boil.

Step 2: Incorporate the Marshmallow Fluff

Remove the saucepan from heat and immediately stir in the 1 jar Marshmallow Fluff. The heat from the sugar mixture will begin melting the fluff, but you’ll need to work quickly as it thickens fast.

Fold the fluff in with a spatula, pressing down to break up any large chunks. The mixture will become thick and sticky, almost like a very dense cake batter. This transformation usually takes 1-2 minutes of vigorous stirring.

If the mixture seems too thick to stir, return it to low heat for 30 seconds just to soften it slightly, but don’t overheat or the sugar will start to separate.

Step 3: Add Flavorings and Finish the Mixture

Stir in the 1 tsp Vanilla Extract and 0.25 tsp Salt. The vanilla adds that classic depth of flavor, while the salt balances all the sweetness perfectly. Mix until these are fully incorporated and the fudge has a uniform color.

At this point, the fudge should be pulling away from the sides of the pan slightly and have a glossy, thick consistency. If it’s still too runny, return it to low heat for another 1-2 minutes, stirring constantly.

Step 4: Set and Cut the Fudge

Line an 8×8-inch or 9×9-inch baking pan with parchment paper, leaving some overhang on the sides for easy removal. Pour the fudge mixture into the pan and spread it evenly with a spatula.

Let it cool at room temperature for 1 hour, then refrigerate for at least 2 hours until completely set. The fudge is ready when it’s firm to the touch and doesn’t stick to your finger when pressed lightly.

Once fully set, lift the fudge out using the parchment overhang and place it on a cutting board. Cut into 16 equal squares using a sharp knife. For a finishing touch, dust with 0.5 cup Powdered Sugar if desired.

Dietary Considerations for These Flavors

Gluten-Free Friendly

This no-bake treat is naturally gluten-free, making it safe for those with celiac disease or gluten sensitivity. None of the core ingredients—peanut butter, sugar, or marshmallow fluff—contain gluten, so you can enjoy it worry-free. 💪

Dairy Alternatives

To make this dairy-free, simply swap the unsalted butter for 1 stick (½ cup) dairy-free margarine or coconut oil. Brands like Earth Balance work perfectly and maintain the same creamy texture. The flavor remains just as rich.

Vegan Adjustments

For a fully vegan version, use the dairy-free butter mentioned above and ensure your peanut butter and marshmallow fluff are vegan-certified. Dandies makes a great vegan marshmallow fluff substitute. The results are just as indulgent.

Nut Allergy Warning

Since peanut butter is the star ingredient, this recipe isn’t suitable for those with peanut allergies. For tree nut allergies, check labels—some marshmallow fluff brands may have cross-contamination warnings. Always verify ingredient sources.

Sugar Variations

To reduce refined sugar, try substituting coconut sugar for the granulated sugar. Note that the texture may be slightly grainier. For a sugar-free option, use monk fruit sweetener blends, but expect a firmer texture and aftertaste. 💡

Lower-Calorie Option

Cut calories by using powdered peanut butter (like PB2) for half the peanut butter amount. Reconstitute ½ cup powdered peanut butter with ¼ cup water and mix it in with the regular peanut butter. The flavor stays strong while reducing fat.

Frequently Asked Questions