Easy Microwave Peanut Butter Fudge

Ingredients

• 450 gicing sugar, sifted
• 250 gsmooth or crunchy peanut butter
• 230 gunsalted butter
• 1 teaspoonvanilla extract

Instructions

1. 1

   Line the tin

   Line a 20 cm square tin with baking parchment, leaving enough overhang on the sides to lift the fudge out later.

2. 2

   Prepare the sugar

   Sift the icing sugar into a large bowl. If you prefer not to sift it, break up any visible lumps with a fork.

3. 3

   Combine the fats

   Put the unsalted butter, peanut butter and vanilla extract in a microwave-safe bowl.

4. 4

   Melt the mixture

   Microwave for 2 minutes, stirring once halfway through, until the mixture is melted and runny.

5. 5

   Stir until smooth

   Mix thoroughly with a spatula or spoon until the melted ingredients are smooth and well combined.

6. 6

   Add the sugar

   Pour the melted peanut butter mixture into the bowl of icing sugar.

7. 7

   Mix the fudge

   Stir until all the icing sugar is incorporated, scraping up any from the bottom of the bowl. Pressing and squashing the mixture with the spatula helps work the sugar in; continue until it is evenly smooth.

8. 8

   Fill the tin

   Spoon the fudge mixture into the prepared tin.

9. 9

   Level the surface

   Press the mixture into the corners and smooth the top. An offset spatula is useful for making the surface even.

10. 10

    Chill until firm

    Refrigerate for at least 1 hour, or longer, until the fudge has cooled and set.

11. 11

    Mark the pieces

    Lift the set fudge onto a chopping board and score the top to mark where you want to cut.

12. 12

    Cut into squares

    Use a large, sharp knife to cut the fudge along the scored lines.

What is peanut butter fudge?

Fudge is a sweet confection traditionally made by cooking sugar with ingredients such as butter and milk until it sets. This easy version takes a shortcut: icing sugar is mixed with melted butter and peanut butter, then chilled rather than cooked on the hob.

Peanut butter gives the pieces their nutty flavour, while the fine sugar helps create a dense, smooth texture. The microwave makes the melting step quick and straightforward.

Nutrition and macros by portion

The nutrition label shows one serving as written: 72 calories, 2g protein, 9g carbs, 4g fat.

The icing sugar supplies most of the carbohydrates, while the peanut butter contributes protein and both it and the butter contribute fat. Pair a small piece with fresh fruit for a simple way to balance the sweetness.

Why these ingredients work

Icing sugar: sift it if you can, since lumps are harder to work into the thick mixture once the melted ingredients are added.

Peanut butter and butter: together they make the mixture rich and easy to stir while warm. Smooth peanut butter gives an even texture; crunchy peanut butter leaves little nut pieces throughout.

Vanilla: a small amount rounds out the peanut butter flavour without taking over.

Getting the mixture smooth

Stir the melted ingredients before adding them to the sugar so the butter and peanut butter are evenly combined. Then scrape the bottom and sides of the sugar bowl as you mix, where dry patches can linger.

Pressing the mixture against the side of the bowl with a spatula helps incorporate stubborn icing sugar. Stop once there are no obvious dry pockets and the mixture looks consistent.

Setting and slicing

Line the tin with parchment overhanging the sides so you can lift out the chilled block without prising at the edges. Press the mixture into the corners before smoothing the top.

Chill for at least 1 hour, and give it longer if the centre still feels soft. Scoring the top before cutting helps guide the knife into more even pieces.

Choosing the tin and portions

A 20 cm square tin gives the mixture a compact shape that is easy to chill and cut. The recipe makes 64 pieces, so keep the scored lines close together for small, shareable squares.

A sharp knife gives cleaner edges; wipe it between cuts if fudge begins to cling to the blade.

Serving ideas

Serve the squares chilled or let them sit briefly at room temperature for a softer bite. Their sweetness and richness make them well suited to a small after-dinner treat.

For a simple spread, pair them with fresh fruit or serve alongside tea or coffee.

Recipe notes & tips

• Use a bowl large enough to mix the sugar and melted ingredients without spilling.
• Stir the melting mixture halfway through so it heats more evenly.
• Scrape the bottom of the bowl while mixing to catch any dry icing sugar.
• Leave parchment overhanging the tin to make lifting out the fudge easier.
• Score the surface before cutting to help keep the pieces even.

Variations

• Use crunchy peanut butter: it gives the fudge a little texture.
• Add a chocolate drizzle: drizzle melted chocolate over the set fudge and let it firm before cutting.
• Finish with flaky salt: sprinkle a little over the surface before chilling.
• Add chopped peanuts: fold them into the mixture for extra crunch.
• Make smaller squares: cut the set fudge into more pieces for bite-sized servings.

Common mistakes to avoid

• Skipping the sift: lumps may remain in the finished fudge; sift the sugar or break up visible lumps with a fork.
• Overheating the mixture: it may become too hot or separate; microwave for 2 minutes and stir halfway through.
• Leaving dry sugar behind: the fudge can have powdery patches; scrape and press the mixture against the bowl as you stir.
• Not filling the corners: the slab may set unevenly; press the mixture into each corner before smoothing.
• Cutting too soon: soft fudge can be difficult to slice neatly; chill it for at least 1 hour and longer if needed.

How to store

Keep the fudge in an airtight container in the fridge for up to 2 weeks. Separate layers with baking parchment to help prevent the pieces sticking together.

Frequently asked questions