Name: Lemon Oatmeal Crumble Bars
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: American
Ingredients: 1 ½ cups rolled oats; 1 ¼ cups all-purpose flour; ½ teaspoon baking soda; ¼ teaspoon salt; ½ cup brown sugar; ⅓ cup granulated sugar; ¾ cup unsalted butter, melted; 1 teaspoon vanilla extract; 1 (14-ounce) can sweetened condensed milk; ¼ cup fresh lemon juice (about 2 lemons); 1 tablespoon lemon zest

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Bright and zesty, these Lemon Oatmeal Crumble Bars bring together a tangy lemon filling and a buttery oat crumble crust for the ultimate sweet-tart treat. I love how each bite gives a chewy texture from the oats paired with the creamy citrus filling. They're easy to bake, quick to cool, and always a hit whether I'm serving them at a gathering or just craving something cozy at home.

Lemon Oatmeal Crumble Bars

Ingredients

(Tip: You'll find the full list of ingredients and measurements in the recipe card below.)

For the crust and crumble:

1 ½ cups rolled oats

1 ¼ cups all-purpose flour

½ teaspoon baking soda

¼ teaspoon salt

½ cup brown sugar

⅓ cup granulated sugar

¾ cup unsalted butter, melted

1 teaspoon vanilla extract

For the lemon filling:

1 (14-ounce) can sweetened condensed milk

¼ cup fresh lemon juice (about 2 lemons)

1 tablespoon lemon zest

Directions

I preheat the oven to 350°F (175°C) and line an 8x8-inch baking dish with parchment paper, leaving a bit of overhang so I can easily lift the bars out later.

In a large bowl, I combine the oats, flour, baking soda, salt, brown sugar, and granulated sugar.

Then I stir in the melted butter and vanilla extract until the mixture becomes crumbly.

I press about two-thirds of this mixture firmly into the bottom of my prepared pan to form the crust.

In a separate bowl, I whisk together the sweetened condensed milk, lemon juice, and lemon zest until it's smooth and creamy.

I pour that luscious lemon filling over the crust and spread it out evenly.

Then I sprinkle the remaining oat crumble mixture on top.

I bake the bars for 25–30 minutes, or until the top is lightly golden and the filling looks just set.

After baking, I let them cool completely in the pan, then pop them in the fridge for at least an hour before slicing.

Servings and timing

Servings: 12 bars

Prep Time: 15 minutes

Cook Time: 30 minutes

Total Time: 45 minutes

Calories per serving: 310 kcal

Variations

I sometimes like to mix things up with a few tweaks:

Berry twist: I add a handful of fresh raspberries or blueberries on top of the lemon layer before the crumble topping.

Gluten-free version: I use a gluten-free flour blend and certified gluten-free oats to make these friendly for sensitive diets.

Coconut flair: Shredded coconut mixed into the crumble adds extra texture and flavor.

Extra zest: I increase the lemon zest for an even punchier citrus flavor.

Storage/Reheating

I store the bars in an airtight container in the refrigerator for up to 5 days. They taste great cold, but if I prefer them slightly warm, I pop a bar in the microwave for about 10–15 seconds. For longer storage, I freeze them between layers of parchment paper in a sealed container for up to 2 months.

FAQs

How do I know when the bars are done baking?

I look for a lightly golden top and a filling that looks just set but not too jiggly. Overbaking can dry out the filling, so I keep a close eye during the last few minutes.

Can I use bottled lemon juice instead of fresh?

I could, but I really recommend using fresh lemon juice and zest—the flavor is so much brighter and more natural.

Do these bars need to be refrigerated?

Yes, I always refrigerate them after cooling. The lemon filling sets best in the fridge, and it also helps the bars hold their shape when sliced.

Can I double the recipe?

Definitely. I double everything and bake it in a 9x13-inch pan. I usually add a few more minutes to the baking time—around 5–10 extra minutes.

Why is my crust crumbly and not holding together?

That might happen if the oat mixture wasn’t pressed firmly enough into the pan or if it was too dry. I make sure the butter is fully incorporated and press the base down tightly before baking.

Conclusion

These Lemon Oatmeal Crumble Bars are a simple but impressive treat that I can count on every time I want a burst of citrusy sweetness. Whether I’m baking for guests or just need something bright and cozy to snack on, these bars hit the spot. They're easy, satisfying, and always deliver that perfect lemony zing with a buttery oat crunch.

Recipe:

Lemon Oatmeal Crumble Bars

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Author: Cheryl
Total Time: 45 minutes
Yield: 12 bars
Diet: Vegetarian

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Description

Bright and zesty Lemon Oatmeal Crumble Bars with a tangy lemon filling and a buttery oat crumble crust, perfect for any occasion.

Instructions

Preheat the oven to 350°F (175°C) and line an 8x8-inch baking dish with parchment paper, leaving overhang for easy removal.
In a large bowl, mix the oats, flour, baking soda, salt, brown sugar, and granulated sugar.
Stir in the melted butter and vanilla extract until the mixture is crumbly.
Press about two-thirds of the mixture firmly into the bottom of the prepared pan to form the crust.
In a separate bowl, whisk together the sweetened condensed milk, lemon juice, and lemon zest until smooth.
Pour the lemon filling over the crust and spread evenly.
Sprinkle the remaining oat crumble mixture over the lemon filling.
Bake for 25–30 minutes, or until the top is lightly golden and the filling is just set.
Let cool completely in the pan, then refrigerate for at least an hour before slicing.