Banana Blondies Recipe — Golden, Fudgy & Glazed with Creamy Vanilla

There were two bananas sitting on my counter — a little too spotty, a little too soft for the kids to eat straight. I almost made our classic banana oat bars again. Then something stopped me. I wanted something richer. More golden. Something that felt like a real dessert.

Thirty-seven minutes later, these banana blondies recipe came out of the oven — dense, fudgy, and glazed with a silky vanilla frosting. My kids ate three squares each before dinner. No complaints from me.

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Why You’ll Love This Banana Blondies Recipe

Here’s why this one stays in the regular rotation at our house.

• Genuinely fudgy — not cakey. No baking powder, no baking soda. Zero leavening agents means zero air bubbles, and that’s exactly what gives these bars their dense, brownie-like texture. It’s not an accident — it’s the whole point.
• One bowl, no mixer needed. Everything comes together with a spatula and a little patience. You don’t even need a hand mixer for the batter.
• Ripe bananas do the heavy lifting. The naturally sweet caramel notes from your spotty bananas blend into the brown sugar for a depth of flavor that’s warm and wholesome.
• That glaze, though. Creamy, buttery, vanilla — it turns a simple bar into something your friends will ask you to bring to every gathering.
• Healthy blondie recipe at heart. Less sugar than a classic blondie, naturally sweetened by the banana, and baked not fried. Feel good about every square.

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Ingredients & Notes

Everything you need is probably already in your kitchen. A few notes before you start — they make a real difference.

For the Blondie Batter

Ripe bananas — exactly ¾ cup mashed (about 180g / 2 medium very ripe bananas). This is the one measurement I’m strict about. Too much banana brings too much free water into the batter, and your blondies turn gummy and rubbery instead of silky and fudgy. Use a kitchen scale or measure after mashing. If your bananas are large, use just 1½. The spots matter too — the darker the peel, the sweeter and drier the flesh inside.

Unsalted butter, melted — ½ cup (115g / 1 stick). I usually melt it in a small saucepan over medium heat and let it keep going for 3-4 extra minutes until it turns amber and smells nutty. That’s browned butter — it evaporates the water from the butter (which would otherwise add to the banana’s moisture) and doubles the caramel depth. Totally optional, but honestly transformative. If you just melt it normally, the blondies are still wonderful.

Brown sugar, packed — 1 cup (200g). This is what makes a blondie a blondie. The molasses in brown sugar gives that caramel backbone that white sugar simply can’t. Don’t sub it out. If you love our banana chocolate chip cookies, you already know how well brown sugar and banana play together.

Pure vanilla extract — 1 tsp. Don’t skip this. It ties everything together.

1 large egg. Room temperature, if you remember. If not — 5 minutes in a bowl of warm water and you’re good.

Fine salt — ½ tsp. Sounds like a lot. It’s not. Salt is what makes the sweetness pop rather than feel flat.

All-purpose flour — 1 cup (125g). Spooned and leveled, never scooped directly from the bag. Over-measuring flour makes dense bars for the wrong reasons.

For the Vanilla Butter Glaze

Unsalted butter, softened — ¼ cup (60g). Room temperature here — you want it to blend smoothly, not melt into the sugar.

Powdered sugar — 1½ to 2 cups (180-240g). Start with 1½ cups and add more for a thicker consistency.

Heavy cream or milk — 2 to 3 tbsp. This adjusts the spreadability. Add one tablespoon at a time.

Pure vanilla extract — 1 tsp.

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How to Make Banana Blondies

Nine steps, one bowl, no mixer. Let’s go.

Prepare the Batter

1. Prep your pan and preheat. Heat your oven to 350°F (175°C). Line a 9×13 inch (23×33 cm) baking pan with parchment paper and lightly grease it. This is the step that makes slicing clean squares actually possible — don’t skip it.

2. Measure and mash your bananas. Mash exactly ¾ cup (180g) of ripe banana until smooth. A fork works fine — you want a thick purée, not chunky bits. Set it aside.

3. Combine butter and brown sugar. Pour your melted butter (or browned butter, if you’re going that route — see Lily’s Tips) into a large bowl and add the packed brown sugar. Stir with a spatula until fully combined and glossy — about 1 minute. The mixture should look like wet sand.

Butter and brown sugar blended together — already smells like caramel.

4. Add vanilla, egg, and banana. Whisk in the vanilla and egg until the batter is smooth and slightly shiny. Then fold in the mashed banana. The batter will look loose at this stage — that’s normal.

5. Add salt and flour. Don’t overmix. Sprinkle in the salt and flour. Fold gently with the spatula just until no dry flour remains. This is where most people go wrong — overmixing develops gluten and gives you chewy, tough bars. 10 to 12 folds is enough. And remember: there is no baking powder or baking soda in this batter. That’s intentional. Leavening agents create air pockets and lift — which is exactly what we don’t want here. A blondie needs to be dense, not airy.

Bake and Glaze

The batter is thick and golden — pour it into your pan and smooth gently.

6. Bake for 20 to 25 minutes. Spread the batter evenly in the prepared pan and smooth the top. Bake at 350°F (175°C) for 20 to 25 minutes. The edges should be set and lightly golden. The center might still look slightly underdone — that’s fine. It firms up as it cools.

7. Cool completely before glazing. I know this part is hard. But if you spread the glaze on warm blondies, it melts right in and you lose that creamy layer. Wait at least 30 minutes — an hour is better.

8. Make the vanilla glaze and spread. Beat the softened butter with the powdered sugar, vanilla, and 2 tablespoons of cream until smooth and spreadable. Add more cream if needed, one tablespoon at a time. Spread evenly over the cooled blondies with an offset spatula or the back of a spoon.

9. Slice and serve. Slice into 12 to 16 squares using a sharp knife, wiping the blade between cuts for clean edges.

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Lily’s Tips

A few things I’ve learned after making these more times than I can count.

Measure your banana — seriously. The difference between ¾ cup and 1 full cup of mashed banana is the difference between fudgy and gummy. Banana carries a lot of water, and too much of it makes the bars rubbery. I use a measuring cup every single time, even after making these dozens of times.

Try browned butter for a next-level blondie. Instead of just melting your butter, keep it on medium heat for 3 to 4 extra minutes, swirling occasionally, until it turns amber and smells like toasted hazelnuts. It evaporates the residual water in the butter — which matters, because between the butter and the banana you already have a lot of moisture. And the caramel notes? Multiplied by ten.

No leavening — and that’s the point. A lot of people ask me why there’s no baking powder or baking soda in these bars. The answer is simple: those agents create air. Air is what makes a muffin or a cake soft and springy. But a blondie is supposed to be dense, rich, and fudgy — like a brownie without the chocolate. The moment you add leavening, you’ve made banana cake. Leave it out and you get a proper blondie.

Don’t skip the cool time. “The banana bread is not done baking when it comes out of the oven — it finishes as it cools.” Same rule applies here. The bars set up as they rest. Cutting too early gives you soft, crumbling squares instead of clean, fudgy ones.

Brown-spotted bananas contain up to 80% more natural sugar than yellow ones. Those soft, dark-spotted bananas that no one wants to eat straight are the best thing that can happen to this recipe. They sweeten the batter naturally and bring a concentrated banana flavor that under-ripe fruit simply can’t.

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Variations

These bars are wonderful as written — but here are a few directions worth exploring.

Add Mix-ins

Chocolate chip banana blondies. Fold ½ cup (90g) of dark chocolate chips or white chocolate chips into the batter just before pouring into the pan. The chocolate melts into pockets throughout the bars — deeply good. If you love that combo, our banana chocolate chip cookies use the same flavor pairing in a different form.

Pecan banana blondies. Add ½ cup (60g) of roughly chopped pecans to the batter for a nutty crunch against the soft interior.

Change the Base

Gluten free banana blondies. Swap the all-purpose flour 1:1 for a gluten free all-purpose blend (look for one with xanthan gum). The texture is slightly more tender, still fudgy. Our gluten free banana oat cookies follow the same substitution logic if you want to explore that direction further.

Skip the glaze. If you want a lighter bar — closer to a healthy blondie recipe — dust with powdered sugar or simply serve plain. These are honestly great without the frosting too.

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How to Store

Counter: 2 days — the glaze stays soft and the bars stay moist at room temperature in an airtight container.

Fridge: Up to 5 days in an airtight container. Let them come to room temperature for 15 minutes before serving — cold blondies are denser than they should be.

Freezer: Up to 2 months. Freeze unglazed bars individually on a parchment-lined sheet, then transfer to a zip freezer bag. Thaw at room temperature for 1 hour, then glaze fresh before serving.

Meal prep tip: I bake a batch on Sunday, skip the glaze, and freeze individual squares. On busy weeknights I pull one out and glaze it fresh — it takes 3 minutes and feels like a treat every single time. If you’re into batch-prep snacking, our no-bake banana energy balls are another great make-ahead option for the week.

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Signature Lily

These banana blondies have become one of those recipes I come back to again and again — when I need something warm and real, when the bananas are getting too ripe, when I want to bring something to a friend and not show up empty-handed. They’re simple enough for a Tuesday evening and good enough for a weekend dessert table.

If you love these, try our soft banana cake with vanilla glaze or these rich chocolate banana bars next!

Love, Lily 🍌