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These lemon oatmeal crumble bars bring a burst of sunshine and a cozy vibe in every bite. The buttery oat crust pairs perfectly with the zesty lemon layer, making these bars a tasty treat whether you're grabbing a snack or celebrating something special.
I whipped these up on a whim with leftover oats and lemons, and they quickly became a family favorite dessert.
What You Need
- Brown sugar: adds a rich caramel flavor making the crust tastier
- Unsalted butter: softened to blend in smoothly and add richness
- Vanilla extract: gives warmth and a nice aroma
- All-purpose flour: builds structure while keeping things tender
- Baking powder: helps the crumble topping puff up a bit and stay light
- Salt: balances the sweetness and enhances flavors
- Old-fashioned oats: bring chewy texture and hearty taste, rolled oats are best
- Sweetened condensed milk: makes the lemon filling smooth and creamy
- Fresh lemon juice and zest: give a lively bright lemon punch, ripe lemons work best
How To Make It
- Get The Oven And Pan Ready
- Preheat your oven to 350°F and line an 8-inch square pan with parchment paper so the bars come out easy.
- Mix The Crumble
- Beat softened butter and brown sugar in a bowl on medium-high speed for around a minute until creamy. Add vanilla and beat for another 30 seconds.
- Add The Dry Stuff
- Stir in flour, baking powder, salt, and oats. Mix at medium speed until the crumble looks like it holds together when pressed but is still crumbly.
- Make The Crust
- Take just over half of the crumble mix and press it evenly into the bottom of your pan to form the crust.
- Bake The Crust
- Put the pan in the oven and bake the crust for 12 minutes until it sets and starts getting golden. Take it out when ready.
- Whisk The Lemon Filling
- In another bowl, mix the sweetened condensed milk, lemon juice, and zest until smooth and thick. This will firm up in the oven.
- Put It Together
- Pour the lemon filling over the baked crust. Sprinkle the rest of the crumble evenly on top to cover the lemon layer.
- Bake The Bars
- Put the pan back in the oven for another 22 to 25 minutes. The edges should get lightly golden and the center feel firm when touched.
- Let It Cool
- Cool the pan completely on a wire rack so the filling can set just right.
- Slice And Keep
- Lift the bars out using the parchment edges. Cut into squares. Store at room temp for two days or in the fridge up to a week.
The lemon filling is my favorite part, bursting with fresh bright flavor. It takes me back to sunny afternoons when my family snuck these before dinner and loved the sweet and tangy combo.
Keeping Tips
Keep bars in a sealed container to hold moisture. If you pop them in the fridge, let them warm up a bit before eating so they stay soft.
Swap Ideas
You can swap brown sugar for coconut sugar if you want a richer, earthier taste. Quick oats work but the bars won’t be quite as chewy.
Serving Tips
Sprinkle powdered sugar on top for a little extra something or serve with tea or coffee for a nice afternoon pick-me-up.
These bars mix bright lemon with a buttery oat topping for a perfect balance of tartness and texture every time.
Frequently Asked Cooking Questions
- → Which oats work best in the crumble mix?
Use old-fashioned oats for a chewy texture, but quick oats work fine if you want it a bit finer without losing taste.
- → Can I swap lemon juice for other citrus?
Sure, lime or orange juice are okay, but lemon keeps the tart and sweet balance just right.
- → How do I keep the bars from drying out?
Don't bake too long. Pull them out when edges look lightly browned and the middle is set but still a little soft.
- → Is it needed to bake the crumble base before adding lemon?
Yes, baking the base first stops it from getting soggy once you add the lemon layer.
- → What's the best way to keep these bars fresh?
Keep them wrapped tight at room temp for a few days or store in the fridge up to a week.
- → Why soften the butter before mixing it in?
Soft butter blends easier with sugar for a crumbly, tender base without lumps.