Old-Fashioned Peanut Butter Blondies are my kind of bar cookie: chewy, a little dense in a good way, and full of that brown sugar flavor that tastes like a real bake sale treat.
I like this version because the peanut butter comes through clearly, but the texture stays tender instead of dry or crumbly. They slice clean once cooled, and the edges get just a little more set, which I think is the best part.
These are especially good for cookie trays, casual get-togethers, or when I want a dessert that’s easy to portion. I usually add chocolate chips, but they’re also great plain if you want a more old-school peanut butter bar.
Why You’ll Love This Recipe
Soft and Chewy: These stay chewy in the middle with nicely set edges, which is exactly what I want in a blondie.
Big Brown Sugar Flavor: The brown sugar gives that classic old-fashioned taste that works so well with peanut butter.
One-Bowl Friendly: You don’t need anything fancy here, and cleanup is quick.
Chocolate Chip Optional: Add chocolate chips, skip them, or swap in peanut butter chips or butterscotch chips depending on what you’re in the mood for.
Great for Sharing: A 9×9 pan makes neat little squares that are easy to stack on a plate and bring along.
Ingredients You’ll Need
Blondie Batter
- Unsalted butter: Melted butter keeps this simple and gives the bars that slightly dense, chewy feel. Let it cool a bit so it doesn’t scramble the eggs.
- Creamy peanut butter: I stick with creamy for the most consistent texture. Natural peanut butter can work, but the oil separation can make the batter act a little unpredictable.
- Light brown sugar: This is where a lot of that old-fashioned blondie flavor comes from. Dark brown sugar works too if you want a deeper molasses taste.
- Granulated sugar: Just a little helps the top get that thin, shiny look and keeps the sweetness clean.
- Eggs: Room temperature is easiest to mix in smoothly. Cold eggs can make the butter firm up in little bits.
- Vanilla extract: Don’t skip it. It makes the peanut butter and brown sugar taste more “finished.”
- All-purpose flour: I use regular flour here. Measure it lightly so the bars don’t turn dry.
- Baking powder: Gives a little lift so they don’t bake up too heavy.
- Fine salt: Peanut butter needs salt to taste like peanut butter. Fine salt blends in evenly.
Mix-ins (Optional)
- Semi-sweet chocolate chips: Semisweet is my go-to here. Milk chocolate is fine if that’s what you have, but it will be sweeter.
- Chopped peanuts: Adds crunch and a more “peanutty” flavor. I like them best if they’re chopped fairly small so the bars still slice neatly.
Recipe Instructions
- Preheat the oven: Heat the oven to 350°F. Line a 9×9-inch baking pan with parchment paper and lightly grease it.
- Mix the butter and peanut butter: In a large bowl, whisk the melted butter with the peanut butter until smooth.
- Add the sugars: Whisk in the brown sugar and granulated sugar until the mixture looks glossy and well blended.
- Add the eggs and vanilla: Whisk in the eggs and vanilla until fully combined and smooth.
- Add the dry ingredients: Fold in the flour, baking powder, and salt just until you don’t see dry streaks of flour.
- Add the mix-ins: Fold in the chocolate chips and chopped peanuts, if using.
- Spread the batter: Spread the batter evenly into the prepared pan and smooth the top.
- Bake: Bake for 22 to 28 minutes, until the edges are set and lightly browned and the center is just set with a moist crumb.
- Cool and slice: Cool completely in the pan for clean slices, then lift out using the parchment and cut into squares.
Some of my tips!
This is the part that really makes a difference. If you only read one section, make it this one because this is where I share the little trick that helps the recipe turn out so well.
Recipe Tips & Tricks
Use creamy peanut butter. It’s the most reliable here and gives you a smooth batter. If you use natural peanut butter, stir it extremely well first so the oil isn’t separated.
Don’t overmix once the flour goes in. Fold just until the flour disappears. Overmixing makes blondies bake up tougher and less chewy.
Pull them when the center is just set. The middle shouldn’t look wet, but it also shouldn’t look dry and fully firm. They keep setting as they cool.
Line the pan with parchment. It makes it so much easier to lift the whole slab out and slice clean squares. It also helps if a few chocolate chips melt along the edges.
Want thicker bars? Use an 8×8-inch pan and plan on a few extra minutes in the oven. Keep the same doneness cues and don’t wait for the center to look dry.
Make some touches!
There are plenty of easy ways to serve this depending on the occasion. Keep it simple, or add a few small touches to make it feel a little more special.
Serving Suggestions
- Milk: A cold glass of milk is classic with peanut butter bars. It’s especially nice if you add the chocolate chips.
- Coffee: These are really good with coffee, especially something not too sweet like drip coffee or an Americano.
- Ice cream: Serve a blondie square with vanilla ice cream on the side. If you used chocolate chips, a little chocolate sauce is good too.
- Fruit: Fresh berries work well here. Strawberries or raspberries are nice if you want something lighter on the plate.
Save it for later
This section covers how to store leftovers and what parts of the recipe you can prepare ahead of time.
Storage and Make Ahead
Store the blondies airtight at room temperature for up to 4 days. I like to keep them in a single layer if I can, or use parchment between layers so the tops don’t get sticky.
If you want to make this recipe ahead, bake the bars the day before and leave them covered on the counter. They slice even more neatly once they’ve had time to fully cool and set.
For longer storage, you can freeze up to 2 months. Wrap individual squares or freeze them in a container with parchment between layers.
Thaw at room temperature for an hour or two, or overnight in the fridge. If you like them slightly warm, a quick microwave warm-up works fine.
A few quick answers
This section covers a few extra details that may help before you head to the recipe card.
Recipe FAQs
Can I use crunchy peanut butter instead of creamy?
You can, and it tastes good if you like extra texture. I still prefer creamy because it mixes more evenly and the bars slice cleaner.
How do I know when peanut butter blondies are done?
Look for set, lightly browned edges and a center that’s just set when you gently shake the pan. A toothpick should come out with moist crumbs, not wet batter.
Can I bake these in an 8×8 pan?
Yes. The bars will be thicker, and you’ll usually need a few extra minutes in the oven. Keep the doneness cues the same and don’t wait until the center looks dry.
What other mix-ins work besides chocolate chips?
Peanut butter chips and butterscotch chips both work well with the brown sugar flavor. You can also leave the mix-ins out entirely for a simple, old-school peanut butter blondie.
Why did my blondies turn out dry?
Most of the time it’s from a little too much flour or baking a little too long. Measure the flour lightly and pull the pan when the center is just set, not fully firm.
You might also like
Before you go, take a look at a few other recipes below the recipe card. They use similar ingredients in a different way and are worth saving too.
MORE DINNER RECIPES TO TRY
Old-Fashioned Peanut Butter Blondies
INGREDIENTS
Blondie Batter
- 1/2 cup unsalted butter melted and slightly cooled
- 3/4 cup creamy peanut butter
- 1 cup light brown sugar packed
- 1/4 cup granulated sugar
- 2 large eggs room temperature
- 2 tsp vanilla extract
- 1 1/2 cups all-purpose flour
- 1 tsp baking powder
- 1/2 tsp fine salt.
Mix-ins Optional
- 1 cup semi-sweet chocolate chips
- 1/2 cup chopped peanuts.
INSTRUCTIONS
Prep and Pan
- heat oven to 350 F
- line a 9x9 inch baking pan with parchment paper and lightly grease.
Make Batter and Bake
- whisk melted butter with peanut butter until smooth
- whisk in brown sugar and granulated sugar until glossy
- whisk in eggs and vanilla until fully combined
- fold in flour baking powder and salt just until no dry streaks remain
- fold in chocolate chips and chopped peanuts if using
- spread batter evenly into prepared pan
- bake until edges are set and lightly browned and the center is just set with a moist crumb 22 to 28 minutes
- cool completely in pan for clean slices then lift out and cut into squares.
