These oven baked 5-ingredient peanut butter cup blondies are exactly the kind of low-effort dessert that saves the day on a busy weeknight or when you need something sweet for a last-minute gathering. They lean on pantry basics and a bag of mini peanut butter cups for that rich chocolate-peanut butter payoff, and the bar-cookie style keeps things simple since everything bakes up in one pan with minimal fuss.
Serve these blondies slightly warm with a glass of cold milk, hot coffee, or a scoop of vanilla ice cream if you want to make them feel extra special. They also travel well for potlucks, bake sales, and family movie nights, and a sprinkle of flaky salt on top pairs nicely with the sweetness if you like that sweet-salty dessert balance.
Oven Baked 5-Ingredient Peanut Butter Cup Blondies
Servings: 16 blondies
Ingredients
1 cup unsalted butter, melted
2 cups packed light brown sugar
2 large eggs
2 cups all-purpose flour
20 ounces unwrapped mini peanut butter cups
Directions
1. Preheat your oven to 350 degrees Fahrenheit. Grease or line a rimmed metal sheet pan or 9x13-inch metal baking pan with parchment paper for easy cleanup and neat slices.
2. In a large mixing bowl, whisk the melted butter and brown sugar together until smooth and glossy. Add the eggs and whisk again until fully combined.
3. Add the flour and stir with a spatula just until no dry streaks remain. Fold in about three-quarters of the mini peanut butter cups, keeping the rest for the top.
4. Spread the batter evenly into the prepared pan. Press the remaining mini peanut butter cups over the top so every bite gets plenty of candy.
5. Bake for 25 to 30 minutes, or until the top is golden brown and the center is just set. A toothpick inserted into the blondie part should come out with a few moist crumbs, not wet batter.
6. Let the blondies cool in the pan for at least 30 minutes before slicing into squares. For the cleanest cuts, cool completely, then lift out with the parchment and slice with a sharp knife.
Variations & Tips
For cleaner slices: If your peanut butter cups get very soft after baking, chill the pan for 20 to 30 minutes before cutting. That little pause makes a big difference when you want bakery-style squares.
Pan size tip: A 9x13-inch metal pan will give you thicker blondies, while a larger rimmed sheet pan will make them a bit thinner and bake faster. Start checking early if you use a larger pan so they stay chewy.
Extra chocolate version: Stir in up to 1 cup of chocolate chips along with the peanut butter cups for an even richer dessert. This is a good option if you're making these for a party and want a more candy-bar style blondie.
Salted finish: A light sprinkle of flaky sea salt right after baking balances the sweetness and makes the peanut butter flavor pop. It is one of my favorite easy upgrades when I want these to taste a little more special.
Make-ahead tip: These keep well in an airtight container at room temperature for 3 days, or in the fridge for up to 1 week. You can also freeze individual squares and thaw them as needed for an easy lunchbox or after-dinner treat.