Lemon Oatmeal Crumble Bars

This lemon oatmeal crumble bar recipe is a favorite for anytime you want a dessert that feels like sunshine and comfort all in one bite. The buttery oat crust combined with the bright tang of lemon filling makes these bars a wonderful treat whether for a casual snack or a special occasion.

I first made these bars on a whim when I had leftover oats and lemons and they quickly became a requested dessert in my house.

Ingredients

• Unsalted butter: is softened so it blends smoothly, providing richness to the oat crumble
• Brown sugar: gives a deeper caramel note than white sugar would, making the crust more flavorful
• Vanilla extract: enhances the overall aroma and adds warmth
• All-purpose flour: creates structure but keeps the texture tender
• Baking powder: helps the crumb topping rise slightly and stay light
• Salt: is essential to balance sweetness and bring out the flavors
• Old-fashioned oats: add a chewy texture and wholesome taste rolled oats will work best for texture
• Sweetened condensed milk: is key for the creamy lemon filling with a smooth, thick consistency
• Fresh lemon juice and zest: are what give these bars their bright and lively lemon flavor, so use ripe lemons for best results

Instructions

Preheat And Prepare The Pan:

Line an 8-inch square baking pan with parchment paper for easy removal of the bars after baking. Preheat your oven to 350 degrees Fahrenheit.

Make The Crumble Mixture:

In a mixing bowl, beat the softened butter and brown sugar on medium-high speed for about one minute until they are combined and creamy. Add the vanilla extract and beat for an additional 30 seconds.

Add Dry Ingredients:

Add the flour, baking powder, salt, and oats into the butter mixture. Mix on medium speed until the mixture becomes crumbly but holds together slightly when pressed.

Create The Base Layer:

Press just over half of the crumble mixture evenly into the bottom of the prepared pan. This layer will form the crust.

Bake The Crust:

Place the pan in the preheated oven and bake the crust layer for 12 minutes. It should be set and just beginning to turn golden. Remove from the oven to add the filling.

Prepare The Lemon Filling:

In a separate bowl, whisk together the sweetened condensed milk, fresh lemon juice, and lemon zest until smooth and thick. This mixture will set firmly as it bakes.

Assemble The Bars:

Pour the lemon filling evenly over the pre-baked crust layer. Then sprinkle the remaining crumble mixture evenly on top of the lemon filling, covering it lightly but completely.

Bake The Completed Bars:

Return the bars to the oven and bake for an additional 22 to 25 minutes. The edges should turn lightly golden and the center will be firm to touch when done.

Cool Completely:

Let the pan cool completely on a wire rack. This step is important to allow the filling to set properly.

Slice And Store:

Lift the bars out of the pan by pulling the parchment paper edges. Cut into squares and store at room temperature for up to two days or refrigerate up to one week.

My favorite part is the lemon filling which bursts with fresh bright flavor. It reminds me of sunny afternoons when my family would sneak these bars before dinner and smile at the perfect balance of tang and sweetness.

Storage Tips

Store bars in an airtight container to keep them moist. If refrigerated, bring to room temperature before serving to enjoy the soft texture.

Ingredient Swaps

You can swap light brown sugar for coconut sugar for a slightly earthier flavor. Using quick oats is fine but the texture will be slightly less chewy.

Serving Ideas

Dust with powdered sugar for an extra touch or serve alongside a cup of tea or coffee for a delightful afternoon treat.

These bars combine bright lemon flavor with a buttery oat crumble for a perfect balance of tang and texture every time.

Frequently Asked Recipe Questions

→ What type of oats work best for the crumble?

Old-fashioned oats provide a hearty texture, but quick oats can be used for a finer crumble without sacrificing flavor.

→ Can I substitute the lemon juice with another citrus?

Yes, lime or orange juice can be used, though lemon offers the ideal balance of tartness with sweetness.

→ How do I prevent the bars from becoming too dry?

Be careful not to over-bake; remove once the edges turn lightly golden and the center feels set but slightly soft.

→ Is it necessary to pre-bake the crumble crust?

Yes, pre-baking ensures the crust firms up, preventing sogginess when the lemon filling is added.

→ What is the best way to store these bars?

They keep well at room temperature for a couple of days or refrigerated up to a week, wrapped tightly to retain moisture.

→ Why soften the butter before mixing?

Softened butter blends smoothly with sugar, resulting in a tender and crumbly base without lumps.