Aunt Sarah makes this 3 ingredient treat every spring and my kids literally fight over the corner pieces. It sets in the fridge so fast I barely have time to clean the bowl.

This 3-ingredient peanut butter fudge is exactly the kind of recipe I pull out every spring when life feels extra busy but I still want to make something special for my kids. It’s based on my Aunt Sarah’s no-fail fudge, the one she’d whip up in a glass casserole dish while we were still clearing the dinner table. It sets in the fridge incredibly fast—by the time you rinse the mixing bowl, it’s already firming up. The texture is smooth and creamy with those slightly uneven, hand-cut edges that make it feel homemade and nostalgic. If you need a quick treat for a school event, family get-together, or just a random Tuesday, this fudge is as easy as it gets and always disappears first.

Serve the peanut butter fudge chilled, cut into small squares or corner pieces (the most fought-over spots in my house) on a simple platter or right out of the glass casserole dish. It pairs perfectly with a cold glass of milk, hot coffee, or tea. For a spring gathering, I like to mix it onto a dessert tray with fresh berries and a few store-bought cookies to balance the sweetness. It also travels well—just cover the dish tightly and keep it cool, and you’ve got a crowd-pleasing treat ready for potlucks, playdates, or office snack tables.

Servings: 16

1 cup (2 sticks / 226 g) unsalted butter

Lightly grease an 8×8-inch glass casserole dish with nonstick spray or a thin layer of butter. This helps the fudge release easily and gives those slightly uneven, hand-cut edges.

In a medium microwave-safe bowl, add the butter and creamy peanut butter. Microwave on HIGH in 30-second bursts, stirring after each, until the mixture is completely melted and smooth, about 1 1/2 to 2 minutes total. (You can also melt them together in a small saucepan over low heat, stirring constantly.)

Once melted, stir the butter-peanut butter mixture until it looks glossy and fully combined. This is your flavor base, so make sure there are no streaks of plain butter or peanut butter.

Add 3 1/2 cups of powdered sugar to the warm mixture. Using a sturdy spoon or spatula, stir until the sugar is fully incorporated and the mixture becomes thick, smooth, and slightly stiff. If it still looks loose or glossy, sprinkle in the remaining 1/2 cup of powdered sugar a little at a time until the fudge batter is very thick and holds its shape when you drag a spoon through it.

Quickly scrape the fudge mixture into the prepared glass casserole dish while it is still warm and easy to spread. Use the back of the spoon or a spatula to smooth the top into an even layer; don’t stress about perfection—those tiny ridges and hand-smoothed marks are part of the charm.

Place the dish in the refrigerator, uncovered, and let the fudge chill until set, about 20–30 minutes. It will firm up fast, so by the time you’ve washed the bowl and spoon, it’s usually ready to slice.

Once fully set, remove the dish from the fridge. Using a sharp knife, cut the fudge into squares or rectangles directly in the glass dish, pressing down firmly to get those coveted corner pieces. Wipe the knife with a warm, damp cloth between cuts for cleaner edges if you like.

Serve the fudge straight from the chilled dish or transfer the pieces to an airtight container, layering with parchment paper if stacking. Store in the refrigerator for up to 1 week for best texture and flavor.