Introduction

These Lemon Oatmeal Crumble Bars combine a buttery oat crust with a tangy lemon filling for a delightful balance of sweet and tart. They’re easy to make and perfect for a refreshing dessert or snack. With a crumbly topping and zesty lemon flavor, these bars are sure to become a favorite.

A close-up view of a dessert bar with three distinct layers, resting on a white plate placed on a white marbled surface. The bottom layer is light brown and crumbly, looking like a baked crust. The middle layer is thick and creamy, pale yellow in color, resembling a custard or lemon filling. The top layer is a coarse, golden crumb topping with small oats and brown sugar, adding texture and a crunchy look. The dessert piece is cut into a neat square, with more pieces blurred in the background. photo taken with an iphone --ar 4:5 --v 7

Ingredients

7 tablespoons (99g) unsalted butter, softened to room temperature
3/4 cup (150g) light or dark brown sugar, packed
1 teaspoon vanilla extract
1 cup (125g) all-purpose flour (spooned & leveled)
1 teaspoon baking powder
1/4 teaspoon salt
1 cup (85g) old-fashioned oats or quick oats (not instant)
1 can (14 ounces) full-fat sweetened condensed milk
6 tablespoons (90ml) lemon juice (from about 2 lemons)
1 tablespoon lemon zest (from about 1 lemon)

Instructions

Step 1: Preheat the oven to 350°F (177°C). Line an 8-inch square baking pan with parchment paper for easy removal of the bars.
Step 2: In a mixer with a paddle attachment, beat the softened butter and brown sugar on medium-high speed until fully combined, about 1 minute. Scrape down the bowl, then add vanilla extract and beat for 30 seconds more.
Step 3: Add flour, baking powder, salt, and oats to the bowl. Mix on medium speed until combined into a crumbly, dry mixture totaling about 3 to 3.5 cups.
Step 4: Press slightly more than half of the crumble mixture firmly into the bottom of the prepared pan to form the crust. Bake for 12 minutes, then remove from the oven.
Step 5: In a medium bowl, whisk together the sweetened condensed milk, lemon juice, and lemon zest until smooth and thick.
Step 6: Pour the lemon filling over the warm crust and spread evenly. Sprinkle the remaining crumble mixture on top.
Step 7: Bake the bars for 22 to 25 minutes, until the edges are lightly golden and the center is set. Avoid over-baking.
Step 8: Remove from the oven and cool completely on a wire rack. Use the parchment paper to lift the bars from the pan, then slice into squares.

Tips & Variations

For extra texture, toast the oats lightly before mixing into the crumble.
You can substitute lime juice and zest for a fresh twist on flavor.
If you prefer a less sweet filling, reduce the sweetened condensed milk slightly and add a bit more lemon juice.
Use quick oats for a finer crumb or old-fashioned oats for a chewier texture.

Storage

Store leftover bars at room temperature in an airtight container for up to 2 days. For longer storage, refrigerate for up to 1 week. To serve, bring bars to room temperature or warm slightly for a soft and tender bite.

How to Serve

This image shows a close-up of a dessert bar with three visible layers. The bottom layer is a crumbly, light brown crust with a slightly rough texture. The middle layer is a thick, creamy yellow filling that looks smooth and soft. The top layer is a crumb topping made of small, golden brown clusters, giving a crunchy appearance. The dessert piece is placed on a simple white plate, set on a white marbled textured surface. Photo taken with an iphone --ar 4:5 --v 7

Serve this delicious recipe with your favorite sides.

FAQs

Can I use lemon juice from a bottle instead of fresh lemons?

Fresh lemon juice is best for the bright, natural flavor, but bottled lemon juice can be used in a pinch. Adjust the quantity to taste, as bottled juice is often more concentrated or less vibrant.

Can I make these gluten-free?

Yes, substitute the all-purpose flour with a gluten-free flour blend that measures like regular flour. Ensure oats are certified gluten-free as well to avoid cross-contamination.