Lemon Crumb Bars

Alright, these lemon crumb bars? They’re tangy, sweet, and topped with a buttery, crunchy crumb that’s just perfect. Like a bright lemon filling wrapped in a cozy, crumbly hug.

I made them on a sunny afternoon when I wanted something fresh but easy. Whipped up a simple lemon curd layer, baked it over a buttery crust, and sprinkled the top with a crumbly streusel. The smell while baking? So good.

They’re great for parties, snacks, or anytime you want a slice of sunshine. Easy to slice, easy to share, and hard to resist. Let’s bake a batch—you’re gonna love every bright, buttery bite.

Why You’ll Love This Recipe

• Bright and Fresh Flavor: The lemon filling is made with real lemon juice and zest, giving each bar a clean, citrusy flavor without being overpowering.
• Perfect Texture Contrast: The base and crumble topping are slightly crisp with a hint of chewiness from the oats, which balances the silky lemon layer in the middle.
• No Mixer Required: This is a bowl-and-spoon kind of recipe. No special equipment, no complicated steps—just stir, layer, and bake.
• Great for Make-Ahead: These bars slice better when chilled, so they’re ideal for preparing a day in advance.
• Freezer Friendly: Make a batch, freeze the leftovers, and enjoy whenever you need a quick dessert or sweet snack.

What You Need to Know Before You Start

Prep Time & Cook Time:

• Prep Time: 25 minutes (including zesting and juicing lemons, and mixing crust/filling)
• Bake Time: 35 minutes
• Chill Time (mandatory for clean slicing): At least 2 hours in the fridge, or overnight
• Total Time: Just over 3 hours (most of it hands-off)

Servings:
Makes 16 small bars or 9 large ones, depending on how you slice them. These are rich and flavorful, so smaller portions go a long way.

Difficulty Level:
Beginner-friendly. If you can melt butter, whisk eggs, and juice a lemon, you can absolutely make this recipe.

Required Kitchen Tools

Here’s what you’ll need to successfully pull this recipe together:

• 8×8-inch baking pan: Glass, metal, or ceramic all work.
• Parchment paper: Helps lift the bars out cleanly—especially important for crumb bars.
• Mixing bowls: One medium (for filling) and one large (for crust and topping).
• Whisk and spoon: A whisk is best for combining the lemon filling, and a sturdy spoon or spatula is great for mixing the crumb base.
• Zester or microplane: A fine grater to get the most flavor from your lemons.
• Manual juicer or fork: Fresh lemon juice makes a difference. If you don’t have a juicer, press and twist with a fork.
• Measuring cups and spoons: Accurate measurement keeps the texture just right.
• Knife: For clean slicing once chilled.

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Ingredients for Lemon Crumb Bars

This recipe relies on simple, pantry-friendly ingredients. The lemon filling uses sweetened condensed milk, which gives a custardy consistency without the need for extra sugar or cream.

For the Crumb Base & Topping:

These ingredients make both the bottom layer and the topping. You’ll use most for the base and reserve a portion for the top.

• 1 cup (130g) all-purpose flour: Standard flour provides structure to the crust.
• 1 cup (80g) old-fashioned rolled oats: Adds texture and heartiness. Avoid quick oats—they’ll make the bars too soft.
• ½ teaspoon baking soda: Helps slightly lighten the crust so it isn’t too dense.
• ¼ teaspoon salt: Balances the sweetness and sharp lemon notes.
• ½ cup (113g) unsalted butter, melted: Melted butter binds the dry ingredients and gives the crust a rich, shortbread-like base.
• ⅓ cup (70g) packed light brown sugar: Sweetens the crust while giving a subtle molasses flavor and moisture.
• 1 teaspoon pure vanilla extract: Adds depth to the oat layer and rounds out the buttery notes.

For the Lemon Filling:

This filling is smooth, creamy, and lightly tart. It sets as it bakes and becomes even more sliceable once chilled.

• 1 (14-ounce) can sweetened condensed milk: Gives the filling body, richness, and sweetness.
• 2 large egg yolks: Help thicken the filling and add a custard-like texture.
• ½ cup (120ml) freshly squeezed lemon juice: About 2–3 medium lemons. Use fresh juice for the cleanest flavor.
• 1 tablespoon lemon zest: This is the flavor boost that makes the lemon pop. Zest before juicing.
• 2 tablespoons sour cream (or plain yogurt): Adds slight tang and creaminess, helping the filling stay smooth when baked.

How to Make Lemon Crumb Bars: Step-by-Step Instructions

These bars come together in just a few easy steps. You’ll make one mixture for both the crust and crumble topping, then whisk together a creamy lemon filling before layering and baking. Be sure to let them cool fully and chill before slicing for the cleanest cuts.

1. Preheat and Prepare Your Pan

• Preheat your oven to 350°F (175°C).
• Line an 8×8-inch square baking pan with parchment paper, leaving an overhang on two sides to help lift the bars out later. Lightly grease the sides if not using parchment.

2. Make the Crumb Base and Topping

• In a large mixing bowl, stir together:
  • 1 cup all-purpose flour
  • 1 cup old-fashioned oats
  • ½ teaspoon baking soda
  • ¼ teaspoon salt
• Pour in:
  • ½ cup melted unsalted butter
  • ⅓ cup packed light brown sugar
  • 1 teaspoon vanilla extract
• Stir until everything is evenly moistened and crumbly. The mixture should resemble damp sand with some oat clusters.
• Set aside ¾ cup of this mixture for the topping. The rest will become your base.

3. Press and Bake the Crust

• Transfer the remaining crumb mixture into the prepared pan.
• Use the back of a spoon, spatula, or clean hands to firmly press it into an even, compact layer. Try to fill all corners evenly.
• Bake for 10–12 minutes, just until lightly golden.
  This par-baking step helps the base hold up under the moist filling.
• Remove from oven and let it cool slightly while you prepare the filling.

4. Make the Lemon Filling

• In a medium mixing bowl, whisk together:
  • 1 can (14 oz) sweetened condensed milk
  • 2 large egg yolks
  • ½ cup fresh lemon juice
  • 1 tablespoon lemon zest
  • 2 tablespoons sour cream or plain yogurt
• Whisk until smooth and fully combined.
  The mixture will be slightly thick but still pourable. It should look pale and glossy.

5. Assemble the Bars

• Pour the lemon filling over the slightly cooled crust. Spread it gently with a spatula to make an even layer.
• Sprinkle the reserved crumb mixture evenly across the top. It won’t fully cover the filling—that’s okay. The exposed filling will set and the topping will turn golden and slightly crisp.

6. Bake

• Bake the bars in the preheated oven at 350°F (175°C) for 22–25 minutes, or until the edges are lightly golden and the center no longer jiggles when you gently shake the pan.
• Tip: The bars will firm up more as they cool, so don’t overbake.

7. Cool and Chill

• Remove the bars from the oven and let them cool completely at room temperature, about 1 hour.
• Once cooled, refrigerate for at least 2 hours, preferably longer, to allow the filling to fully set and make slicing easier.

Serving and Presentation Ideas

Once the bars are fully chilled, use the parchment overhang to lift them from the pan onto a cutting board. Use a sharp knife to slice them into:

• 16 small squares for bite-sized servings
• 9 larger squares if serving as a more substantial dessert

For a clean presentation, wipe the knife between each cut.

Optional: Lightly dust the tops with powdered sugar or garnish each bar with a tiny twist of lemon zest before serving.

How to Store Lemon Crumb Bars

• In the Fridge: Store in an airtight container in the refrigerator for up to 5 days. They taste even better the next day as the flavors settle.
• In the Freezer: Layer bars between parchment paper in an airtight container and freeze for up to 2 months. Thaw in the refrigerator before serving.

Tips and Tricks for Success

• Use fresh lemon juice and zest. Bottled juice lacks brightness and won’t deliver the same flavor.
• Don’t skip chilling. This is the key to clean cuts and a firm filling.
• Press the crust tightly. A well-packed base will hold up better and slice neatly.
• Don’t overmix the filling. Just whisk until smooth—no need to incorporate air.
• Check bake time early. Ovens vary. Start checking at 22 minutes.

Nutrition

Serving Size	1 bar (1 of 16)
Calories	215
Total Fat	9g
Saturated Fat	5g
Carbohydrates	30g
Sugar	18g
Protein	3g
Fiber	1g
Sodium	85mg

Nutrition values are approximate and may vary based on brands used.

Lemon Crumb Bars FAQs

Can I use bottled lemon juice?
Fresh juice is strongly recommended. Bottled lemon juice lacks the natural flavor depth and can taste flat.

Can I double this recipe?
Yes. Double the ingredients and use a 9×13-inch pan. Baking time may increase slightly—watch for the center to be just set.

Can I make it dairy-free?
You can experiment with coconut condensed milk and a dairy-free yogurt, but texture and flavor will vary.

Do these need to be refrigerated?
Yes. Because of the egg yolks and dairy-based filling, keep them chilled until serving.

Conclusion

These Lemon Crumb Bars combine a golden oat crust with a cool, creamy lemon center—perfect for those who enjoy desserts that are both bright and comforting. Whether you’re making them for a gathering or just a quiet afternoon treat, they’re easy to prepare and even easier to love.