Looking for a zesty dessert that’s both bright and comforting? These Lemon Crumb Bars combine a buttery oat-packed crust and crumble topping with a smooth, sweet-tart lemon filling that will have everyone coming back for seconds. Whether you’re serving them at a spring brunch, summer picnic, or holiday potluck, these citrusy squares are a make-ahead gem that slice beautifully and taste even better the next day!
💛 Why You’ll Love These Lemon Crumb Bars
- Bright, bold lemon flavor in every bite
- Buttery oat crumble texture that’s both soft and crispy
- Simple, pantry-friendly ingredients
- Perfect for make-ahead desserts
- Easily sliced for serving or gifting
🛒 Ingredients for Tangy Lemon Crumb Bars
✨ For the Crust & Topping
- 1¼ cups all-purpose flour
- 1¼ cups old-fashioned rolled oats
- ½ tsp baking soda
- ½ tsp salt
- ½ cup granulated sugar
- ½ cup light brown sugar, packed
- ¾ cup unsalted butter, melted
- 1 tsp vanilla extract
🍋 For the Lemon Filling
- 1 can (14 oz / 396g) sweetened condensed milk
- 2 large egg yolks
- 2 tbsp lemon zest (about 2 lemons)
- ½ cup fresh lemon juice (never bottled!)
👩🍳 How to Make the Best Lemon Crumb Bars
1. Preheat & Prep
Preheat oven to 350°F (175°C). Grease an 8×8-inch pan or line with parchment paper for easy removal.
2. Make the Crumble
In a large bowl, whisk together flour, oats, baking soda, salt, and both sugars. Add melted butter and vanilla. Stir until combined and crumbly.
3. Bake the Base
Press half of the crumb mixture into the bottom of the prepared pan. Pack it down firmly using your hands or the bottom of a measuring cup.
Bake for 15 minutes, just until lightly set.
4. Prepare the Filling
In a separate bowl, whisk together condensed milk, lemon juice, lemon zest, and egg yolks until silky and slightly thickened.
5. Assemble
Pour the lemon filling over the baked base and spread evenly. Sprinkle remaining crumble mixture over the top.
6. Bake Again
Return to oven and bake for 20–22 minutes, or until the topping is golden and the filling looks just set with a gentle wobble.
7. Cool & Chill
Cool completely on the counter, then chill in the fridge for at least 2 hours (overnight is best!). Slice into 16 neat squares for serving.
💡 Pro Tips for Success
- Pre-bake the crust to avoid a soggy bottom
- Chill thoroughly before slicing for clean edges
- For a decorative touch, dust with powdered sugar before serving
- Use room temp eggs for a smoother filling
- Avoid the bitter white pith when zesting lemons
🔄 Variations & Creative Twists
- 🥥 Add ¼ cup toasted coconut to the crust for a tropical spin
- 🫐 Toss in ½ cup fresh blueberries for a summery twist
- 🍫 Drizzle or dip in white chocolate after chilling for a dessert bar upgrade
- 🍊 Swap lemon juice with orange or lime for a different citrus flavor profile
🧊 Storage & Make-Ahead Tips
- Refrigerator: Store bars in an airtight container for up to 5 days
- Freezer: Freeze individually wrapped bars for up to 3 months
- Thawing: Let sit at room temperature or in the fridge overnight before serving
🍰 Final Thoughts
These Lemon Crumb Bars are the perfect balance of buttery sweetness and citrus zing. Whether you’re baking for a picnic, gifting a homemade treat, or just craving a bright bite of sunshine, these bars are sure to be your new go-to lemon dessert. Bonus: they look just as good as they taste—and no one will guess how easy they are to make!