Name: Lemon Crumb Bars Recipe
Prep time: 15 min
Cook time: 30 min
Total time: 45 min
Cuisine: American
Ingredients: 1 cup all purpose flour; 1 cup old fashioned oats; ¼ teaspoon salt; ¾ teaspoon baking soda; 10 tablespoons unsalted butter (melted); ½ cup light brown sugar (packed); 1 teaspoon vanilla flavoring; 1 (14 oz) can sweetened condensed milk; 2 tablespoons sour cream or plain yogurt; 1 large egg yolk; ¼ cup freshly squeezed lemon juice; 1 generous tablespoon finely grated lemon zest; ½ teaspoon vanilla flavoring

Jump to Recipe· 4.3 from 10 reviews

If you’re looking for a dessert that perfectly balances a tangy citrus punch with a buttery, crumbly crust, then look no further because this Lemon Crumb Bars Recipe is exactly what your kitchen needs. Imagine a golden oat-studded base hugging a luscious lemon custard layer, all topped with a generous sprinkle of crumbly goodness that brings the perfect textural contrast. It’s a delightful treat that’s as simple to make as it is irresistible to eat, guaranteed to brighten any snack time or celebration.

Ingredients You’ll Need

The image shows a four-step process of making a layered oat dessert in a white square baking dish lined with parchment paper on a white marbled surface. The first step shows a rough and textured layer of light brown oats pressed evenly at the bottom and sides. The second step shows a smooth, pale yellow cream layer being poured over the oat base, spreading from the center outward. The third shows the cream layer being spread evenly with a flat metal spatula that has a black handle. The last step displays a second layer of oats sprinkled roughly on top of the cream, with chunks of uneven size and a light golden color. photo taken with an iphone --ar 4:5 --v 7

The magic of this Lemon Crumb Bars Recipe starts with a handful of straightforward, pantry-friendly ingredients. Each one plays a crucial role — from providing rich buttery flavor and a tender oat crust, to delivering that refreshing zing of fresh lemon in the filling.

All-purpose flour, 1 cup: The backbone of the crust, giving structure and a tender crumb.
Old fashioned oats, 1 cup: Adds a hearty, rustic texture that complements the sweetness.
Salt, ¼ teaspoon: Balances the flavors and enhances the sweetness.
Baking soda, ¾ teaspoon: Helps the crust rise just enough for a light texture.
Unsalted butter, 10 tablespoons (melted): Brings richness and helps the crust bind beautifully.
Light brown sugar, ½ cup (packed): Offers subtle molasses undertones that deepen flavor.
Vanilla flavoring, 1 teaspoon (plus ½ teaspoon for filling): Adds a warm aromatic note that brightens the lemon.
Sweetened condensed milk, one 14 oz can: Creates a smooth, creamy base for the luscious filling.
Sour cream or plain yogurt, 2 tablespoons: Keeps the filling tender with a hint of tanginess.
Egg yolk, 1 large: Acts as a binder for the filling’s silkiness.
Freshly squeezed lemon juice, ¼ cup: The star ingredient delivering irresistible citrus zing.
Finely grated lemon zest, 1 generous tablespoon: Intensifies the lemon flavor with aromatic oils.

How to Make Lemon Crumb Bars Recipe

Step 1: Prepare Your Pan and Oven

Start by preheating your oven to 350°F. Line an 8×8-inch pan with foil or parchment paper, making sure to leave an overhang on two sides—this simple trick will make removing your bars a breeze later on. Give the pan a light spray with nonstick spray to prevent any sticking.

Step 2: Mix Dry Ingredients for Crust and Topping

In a medium bowl, whisk together the flour, oats, salt, and baking soda. This dry mix will become the base and the crumbly topping of your bars, so it’s important to get these well combined for even flavor and texture throughout.

Step 3: Combine Wet Ingredients for Crust and Topping

In a larger bowl, vigorously whisk the melted butter, brown sugar, and vanilla flavoring until the sugar dissolves and the mixture becomes glossy—that lively mix really sets the tone for your buttery crust. Fold the dry ingredients in gently with a spatula or wooden spoon until just combined; the dough will be rich and slightly sticky.

Step 4: Press and Bake the Crust

Reserve about ¾ cup of the dough for the topping—that crumbly finish you’ll love. Press the remaining dough evenly into your prepared pan; it may feel soft and buttery but that’s exactly right. Bake this base layer for 10 minutes until it starts to set and takes on a delicate golden hue.

Step 5: Prepare the Filling and Assemble

While the crust bakes, whisk together the sweetened condensed milk, sour cream (or yogurt), egg yolk, lemon juice, lemon zest, and vanilla in a bowl until smooth and fragrant. Once the crust is ready, pour this filling gently over it, making sure not to disturb the soft layer underneath.

Step 6: Add the Crumb Topping and Final Bake

Crumble the reserved dough evenly over the lemon filling—it’s okay if some chunks are bigger than others, that adds to the rustic charm. Return the pan to the oven and bake for another 17 to 20 minutes until the top turns a light golden brown and the filling is set but still tender to the touch. Let your bars cool completely on a wire rack before slicing.

How to Serve Lemon Crumb Bars Recipe

The image shows a close-up of a square dessert bar on a white marbled surface with some crumbs around it. The dessert has three layers: the bottom layer is a light brown, crumbly crust, the middle layer is a creamy pale yellow filling, and the top layer is a chunky, golden oat crumble with a rough texture. In the background, there is another square dessert bar that is slightly out of focus, showing the same layers. A piece is missing from the front bar, revealing the texture of all three layers clearly. Photo taken with an iphone --ar 4:5 --v 7

Garnishes

To take your Lemon Crumb Bars Recipe up a notch, consider dusting the top with a little powdered sugar or adding a few finely grated lemon zest sprinkles fresh from the fruit. For an elegant touch, a few sprigs of fresh mint really complement the lemon’s brightness.

Side Dishes

These bars pair beautifully with a dollop of whipped cream or a scoop of vanilla ice cream, which balances the tartness with creamy softness. A light cup of green tea or a bright herbal tea, like chamomile or lemon verbena, makes a refreshing accompaniment.

Creative Ways to Present

Slice your bars into small squares for a charming bite-size treat at parties or line them up on a pretty platter for an inviting dessert display. You could also layer them in clear glass containers alongside fresh berries for a stunning lemon-themed parfait twist.

Make Ahead and Storage

Storing Leftovers

You can store leftover lemon crumb bars in an airtight container at room temperature for up to two days, but for best flavor and texture, refrigerate them. Chilled bars hold their shape well and keep fresh for about a week.

Freezing

If you want to keep these delicious bars longer, wrap them tightly in plastic wrap and then foil before freezing. They freeze beautifully for up to two months—just thaw overnight in the fridge to enjoy later.

Reheating

To enjoy warm lemon crumb bars, simply microwave a slice for about 15 to 20 seconds or gently warm them in a low oven (around 300°F) for 5 to 7 minutes. Warming brings out the fragrant lemon oils and softens the crumb topping delightfully.

FAQs

Can I use fresh lemon juice instead of bottled?

Absolutely! Freshly squeezed lemon juice is actually preferred in the Lemon Crumb Bars Recipe because it offers the brightest, most natural citrus flavor that really elevates the filling.

What if I don’t have old fashioned oats—can I substitute quick oats?

While old fashioned oats create the ideal texture, quick oats can be used in a pinch. Just be aware the crumb topping might be a little less chewy and more delicate.

Can I make this recipe gluten-free?

Yes! Swap the all-purpose flour for a gluten-free flour blend that measures cup-for-cup, and ensure your oats are certified gluten-free for a safe and tasty alternative.

Is sour cream necessary in the filling?

Sour cream adds moisture and a slight tang that balances the sweetness, but you can substitute plain yogurt as directed or even use crème fraîche for a richer texture.

How should I cut the bars without them crumbling?

For clean slices, wait until the bars have cooled completely—or better yet, chill them for at least an hour before cutting to help the lemon filling set and the crumbs hold together.

Final Thoughts

There’s something wonderfully comforting and joyful about biting into these Lemon Crumb Bars Recipe that makes every moment a little brighter and sweeter. Whether you’re making them for a special occasion or just because, these bars are guaranteed to become a staple you keep coming back to. Give this recipe a go—you’ll soon find it’s a lemony little slice of heaven that everyone will love.