Lemon Oatmeal Crumble Bars

Posted on June 4, 2025

Zesty Lemon Crumble Bars with Oatmeal Topping – Simple & Delicious Dessert

Bright, buttery, and just the right amount of sweet, these Lemon Oatmeal Crumble Bars are the perfect treat when you’re craving something fresh and satisfying. The zesty lemon filling pairs beautifully with a golden, crumbly oat crust and topping—no mixer needed! Whether you’re serving them as a sunny brunch dessert, a quick snack with coffee, or a Pinterest-worthy potluck dish, they’re sure to be a hit. Plus, they’re simple to make with everyday ingredients, so you can whip up a batch anytime the lemon craving strikes.

Why You’ll Love This Recipe

These Lemon Oatmeal Crumble Bars check all the boxes for an easy, feel-good bake. They’re made with simple pantry staples, come together in under an hour, and offer that irresistible mix of tart and sweet. The oatmeal crumble doubles as both the crust and topping, so there’s less fuss and fewer dishes (win!). The lemon layer is bright, creamy, and adds a pop of flavor that cuts through the cozy, buttery oats. Whether you’re baking for a brunch crowd or prepping weekday snacks, these bars are sure to become a staple in your recipe rotation.

Ingredients

This recipe keeps things simple and fuss-free. You likely have most of these ingredients in your pantry already! The crust and topping use the same oat mixture, while the lemon filling comes together with just a few fresh and zesty ingredients.

For the Crust & Crumble Topping:

1 ½ cups old-fashioned rolled oats
1 ¼ cups all-purpose flour
½ cup light brown sugar, packed
¼ teaspoon salt
½ teaspoon baking soda
¾ cup unsalted butter, melted

For the Lemon Filling:

1 (14 oz) can sweetened condensed milk
⅓ cup fresh lemon juice (about 2–3 lemons)
1 tablespoon lemon zest
1 large egg yolk

Optional: powdered sugar for dusting after baking

Instructions

These Lemon Oatmeal Crumble Bars are super easy to throw together—no mixer, no chilling, no fancy tools. Just layer, bake, and enjoy!

Step-by-Step Instructions:

Preheat the oven to 350°F (175°C). Line an 8×8-inch baking pan with parchment paper, leaving some overhang for easy removal.
Make the crumble mixture:
In a large bowl, combine oats, flour, brown sugar, salt, and baking soda. Pour in the melted butter and stir until the mixture is evenly moistened and crumbly.
Press the crust:
Take about 2/3 of the oat mixture and press it firmly into the bottom of the prepared pan. Use the back of a measuring cup or spoon to pack it down evenly.
Mix the lemon filling:
In a medium bowl, whisk together the sweetened condensed milk, lemon juice, lemon zest, and egg yolk until smooth and creamy.
Assemble the bars:
Pour the lemon filling over the crust and spread evenly with a spatula. Sprinkle the remaining oat mixture on top for a crumbly topping.
Bake for 25–30 minutes, or until the edges are lightly golden and the center is set.
Cool completely:
Let the bars cool at room temperature, then chill in the fridge for at least 1 hour before slicing for cleaner edges.
Dust with powdered sugar (optional) just before serving.

Servings and Timing

These bars are just the right size for sharing—or keeping all to yourself (no judgment here!). Whether you’re prepping for a picnic, a brunch table, or just a sweet snack stash, this recipe delivers the perfect batch size.

Servings:

Makes 12–16 bars, depending on how large you cut them.

Timing:

Prep time: 15 minutes
Bake time: 25–30 minutes
Chill time (recommended): 1 hour
Total time: About 1 hour 45 minutes

They’re delicious at room temp, chilled, or even straight from the fridge with a fork and a cozy blanket.

Tips and Variations

Want to mix things up or make these bars your own? Here are some fun twists and helpful tips to keep your Lemon Oatmeal Crumble Bars fresh and fabulous every time.

Tips:

Use fresh lemons for the best flavor—bottled juice just doesn’t give the same zing.
Chill before slicing for cleaner, neater bars (plus, they taste amazing cold).
Line your pan with parchment paper so you can easily lift the bars out once they’re set.

Variations:

Add coconut: Mix ¼ cup shredded coconut into the crumble topping for a tropical touch.
Swap citrus: Try lime or orange juice/zest for a different twist.
Make it gluten-free: Use certified gluten-free oats and a 1:1 gluten-free flour blend.
Berry boost: Add a thin layer of blueberry or raspberry preserves under the lemon layer for fruity flair.

Storage

These bars store beautifully, making them perfect for make-ahead treats or anytime snacking. Here’s how to keep them fresh and delicious:

Storage Guidelines:

Refrigerator: Store bars in an airtight container in the fridge for up to 5 days. They taste great chilled!
Freezer: For longer storage, freeze the bars (cut or uncut) in a freezer-safe container with parchment paper between layers. They’ll keep for up to 2 months.
To serve from frozen: Just thaw in the fridge overnight or let them sit at room temperature for about 30 minutes.

Frequently Asked Questions

1. Can I use bottled lemon juice instead of fresh?
Yes, but fresh lemon juice and zest give the best flavor. Bottled juice can taste flat or overly acidic.

2. What kind of oats should I use?
Old-fashioned rolled oats work best for that perfect crumble texture. Avoid instant or quick oats—they’ll make the crust mushy.

3. Can I make these bars dairy-free?
You can try using sweetened condensed coconut milk and a plant-based butter alternative. Just note the flavor will shift slightly.

4. Do I have to chill them before serving?
While not strictly required, chilling helps the bars firm up for cleaner slices and enhances the flavor.

5. Can I double the recipe?
Absolutely! Use a 9×13-inch pan and increase the baking time by about 5–10 minutes.

6. My bars seem too soft—what happened?
They may need more bake time or chilling. Also, be sure to measure ingredients accurately and pack the crust tightly.

7. Can I make them gluten-free?
Yes! Use gluten-free oats and substitute the flour with a 1:1 gluten-free baking blend.

Conclusion

If you’re looking for a sunny, satisfying treat that’s as easy as it is delicious, these Lemon Oatmeal Crumble Bars are your answer. With their bright lemony center and cozy oat topping, they’re a crowd-pleaser for brunches, bake sales, or just a quiet moment with coffee.

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Lemon Oatmeal Crumble Bars

Why You’ll Love This Recipe