Quick Recipe Version (TL;DR)

Yield: 36 fudge squares
Prep Time: 20 minutes
Cook Time: 10 minutes
Total Time: 2 hours 30 minutes (including cooling)

Quick Ingredients

Butter, for pan (about 1 tsp)
2 cups (400 g) granulated sugar
1 cup (240 ml) evaporated milk
4 tbsp (56 g) unsalted butter
1/4 tsp fine sea salt
1 1/2 cups (about 380 g) creamy peanut butter
2 tsp pure vanilla extract
Optional: 1/2 cup (70 g) chopped salted peanuts
Optional: Flaky sea salt for sprinkling

Do This

1. Butter and line a 9 x 9 inch baking pan with parchment, leaving overhang for easy lifting.
2. In a heavy saucepan, combine sugar, evaporated milk, butter, and salt; cook over medium heat, stirring until sugar melts.
3. Bring to a gentle boil and cook, without stirring, until 234–238°F (soft-ball stage), 6–8 minutes, brushing down sugar crystals if needed.
4. Remove from heat; immediately stir in peanut butter and vanilla until smooth and well combined.
5. Beat the hot fudge mixture with a wooden spoon for 3–5 minutes, until thickened, slightly cooled, and just losing its gloss.
6. Quickly spread into prepared pan, smoothing the top; sprinkle with chopped peanuts and/or flaky salt if using.
7. Cool at room temperature until firm, about 2–3 hours, then cut into 36 small, thick squares.

Why You’ll Love This Recipe

Classic, old-fashioned flavor and dense, creamy texture that tastes like a childhood bake sale favorite.
No oven needed: this is a simple stovetop candy that sets beautifully in a pan.
Uses basic pantry staples and comes together in under 30 minutes of active time.
Perfect for gift tins, potlucks, and family gatherings; easy to cut into neat, generous squares.

Grocery List

Produce: None
Dairy: Unsalted butter, evaporated milk
Pantry: Granulated sugar, creamy peanut butter, pure vanilla extract, fine sea salt, flaky sea salt (optional), salted peanuts (optional)

Full Ingredients

For the Peanut-Butter Fudge

Butter or neutral oil, for greasing pan
2 cups (400 g) granulated sugar
1 cup (240 ml) evaporated milk (shake can well before measuring)
4 tbsp (56 g) unsalted butter, cut into pieces
1/4 tsp fine sea salt (or 1/8 tsp table salt)
1 1/2 cups (about 380 g) creamy peanut butter, room temperature
2 tsp pure vanilla extract

Optional Toppings

1/2 cup (70 g) chopped salted peanuts, for sprinkling
Flaky sea salt, to finish (a small pinch per square, or about 1/2 tsp for the pan)

Step-by-Step Instructions

Step 1: Prepare the pan

Lightly butter the bottom and sides of a 9 x 9 inch (23 x 23 cm) baking pan. Line the pan with a sheet of parchment paper, leaving a 1–2 inch overhang on two opposite sides to create a sling. This makes it easy to lift the fudge out later. Lightly butter the parchment as well.

Set the prepared pan aside. Measure out all remaining ingredients so they are ready to go; once the sugar syrup reaches temperature, you will need to work fairly quickly.

Step 2: Combine sugar, milk, butter, and salt

In a medium, heavy-bottomed saucepan (at least 3-quart capacity), add the granulated sugar, evaporated milk, unsalted butter pieces, and fine sea salt. Stir gently with a wooden spoon or heatproof spatula to combine.

Place the pan over medium heat. Stir constantly at this stage until the butter is melted and the sugar has mostly dissolved, 3–5 minutes. You should no longer feel gritty sugar when you drag the spoon across the bottom.

Step 3: Cook to soft-ball stage

Once the sugar has mostly dissolved, stop stirring. Clip a candy thermometer to the side of the pan, making sure the tip is submerged in the syrup but not touching the bottom of the pan.

Increase the heat to medium or medium-high to bring the mixture to a gentle but steady boil. If sugar crystals form on the sides of the pan, you can carefully brush them down with a pastry brush dipped in hot water. Do not stir while it boils; this helps keep the fudge smooth and creamy.

Cook until the mixture reaches 234–238°F (112–114°C), the soft-ball stage, about 6–8 minutes from the time it starts boiling. If you do not have a thermometer, you can test by dropping a small amount of syrup into a cup of very cold water: it should form a soft ball that flattens when pressed between your fingers.

Step 4: Add peanut butter and vanilla

As soon as the syrup reaches 234–238°F, remove the saucepan from the heat. Let the bubbling subside for about 30 seconds.

Add the peanut butter and vanilla extract all at once. Stir steadily but gently until the peanut butter is fully melted and the mixture is smooth and uniform. Scrape along the sides and bottom so there are no streaks. At this point, it will be glossy and quite fluid.

Step 5: Beat the fudge until thick and creamy

Set a timer for 3 minutes. Using a sturdy wooden spoon or heatproof spatula, beat the fudge mixture by hand. You are looking for it to cool slightly, thicken, and just begin to lose its high gloss. This typically takes 3–5 minutes, depending on your room temperature and how vigorously you stir.

The fudge is ready to pour when it has the texture of thick cake batter or soft peanut butter frosting and is no longer runny. If you beat it too long and it becomes very stiff in the pot, quickly press it into the pan with the back of the spoon; it will still taste great, just be a bit more rustic on top.

Step 6: Spread in pan and add toppings

Immediately scrape the thickened fudge into the prepared pan. Use an offset spatula or buttered spoon to spread it evenly into the corners and smooth the top. Work fairly quickly, as the fudge will continue to set as it cools.

If using chopped salted peanuts, sprinkle them evenly over the surface and gently press them into the warm fudge so they adhere. If you like a sweet-and-salty finish, sprinkle a light pinch of flaky sea salt over the top as well. Avoid adding too much; a little goes a long way.

Step 7: Cool, cut, and serve

Allow the fudge to cool completely at room temperature until firm, 2–3 hours. For very clean cuts, you can chill the pan in the refrigerator for 20–30 minutes once it reaches room temperature, but do not refrigerate it from the start, or it may set unevenly.

When firm, use the parchment sling to lift the block of fudge out of the pan and transfer it to a cutting board. Use a long, sharp knife, wiping the blade between cuts, to slice the fudge into 6 rows by 6 rows (36 thick squares). Serve at room temperature for the creamiest texture.

Pro Tips

Use a heavy-bottomed pan: A sturdy saucepan prevents hot spots that can scorch the sugar and milk. Thin pans make it much harder to get consistent results.
Do not stir once boiling: Stirring after the mixture starts to boil can encourage sugar crystals to form, giving your fudge a gritty texture instead of a creamy one.
Check your thermometer: If your candy thermometer is older, test it in boiling water. It should read 212°F (100°C); adjust your target temperature slightly if it runs hot or cold.
Have everything measured beforehand: Once the syrup hits soft-ball stage, you need to move fast. Pre-measuring peanut butter and vanilla makes this stress-free.
Cut small but tall squares: This fudge is rich. Cutting 36 smaller, thick pieces gives that classic candy-shop look and just the right portion.

Variations

Crunchy peanut fudge: Swap half of the creamy peanut butter for crunchy peanut butter, and still add chopped peanuts on top for extra texture.
Chocolate-swirled peanut fudge: Melt 1/2 cup (85 g) semisweet chocolate chips and drizzle over the freshly spread fudge. Drag a knife through in gentle figure eights to create swirls before it sets.
Extra-salty peanut butter fudge: Use salted butter instead of unsalted and top generously with flaky sea salt for a bolder sweet-and-salty profile.

Storage & Make-Ahead

Once completely cool and cut, store the fudge squares in an airtight container at cool room temperature for up to 1 week. To prevent sticking, layer the squares between sheets of parchment or wax paper. For longer storage, refrigerate for up to 2 weeks; bring to room temperature before serving for the best texture.

The fudge also freezes very well. Place cut pieces in a single layer on a baking sheet to freeze, then transfer to an airtight container or freezer bag with parchment between layers. Freeze for up to 2–3 months. Thaw in the refrigerator overnight or at room temperature for a few hours, with the container closed to avoid condensation forming on the surface.

Nutrition (per serving)

Approximate values per square (1 of 36, without optional toppings): about 130 calories; 6 g fat; 3 g protein; 18 g carbohydrates; 16 g sugar; 0.5 g fiber; 70 mg sodium. These numbers are estimates and will vary with brands of peanut butter and any toppings you add.

Old-Fashioned Peanut Butter Fudge Squares