They start with a buttery brown sugar oatmeal crust, are layered with a smooth and creamy lemon filling, and finished with a golden crumble topping that adds the perfect texture. Sweet, tangy, soft, and slightly crisp — every bite is pure comfort with a bright citrus twist.
Perfect for potlucks, spring gatherings, afternoon treats, or whenever you need an easy crowd-pleasing dessert!
🍋 Lemon Oatmeal Crumble Bars
Yield: 16 bars
Prep Time: 15 minutes
Bake Time: 38 minutes
Total Time: 53 minutes
Ingredients
For the Crust & Crumble Topping:
- 7 tablespoons unsalted butter, softened
- 3/4 cup packed brown sugar (light or dark)
- 1 teaspoon vanilla extract
- 1 cup all-purpose flour
- 1 teaspoon baking powder
- 1/4 teaspoon salt
- 1 cup old-fashioned oats (quick oats work too — not instant)
For the Lemon Filling:
- 1 (14-ounce) can full-fat sweetened condensed milk
- 6 tablespoons fresh lemon juice (about 2 lemons)
- 1 tablespoon lemon zest
Instructions
1️⃣ Prep the Pan
Preheat oven to 350°F (177°C). Line an 8-inch square baking pan with parchment paper, leaving an overhang for easy removal.
2️⃣ Make the Crust & Crumble
In a large bowl, beat the softened butter and brown sugar together until combined (about 1 minute).
Add vanilla extract and mix again until incorporated.
Add flour, baking powder, salt, and oats. Mix until a crumbly dough forms. The texture should be slightly dry but clump together when pressed.
3️⃣ Form the Crust
Press slightly more than half of the mixture firmly into the bottom of the prepared pan to create the crust.
Bake for 12 minutes, then remove from oven.
4️⃣ Prepare the Lemon Filling
In a medium bowl, whisk together the sweetened condensed milk, lemon juice, and lemon zest until thick and smooth.
5️⃣ Assemble
Pour the lemon filling over the warm crust and spread evenly.
Sprinkle the remaining crumble mixture over the top.
6️⃣ Bake
Return to the oven and bake for 22–25 minutes, until the edges are lightly golden and the center is set. Avoid over-baking.
7️⃣ Cool & Slice
Allow bars to cool completely in the pan.
Lift out using parchment paper and cut into squares.
Storage
- Store at room temperature for up to 2 days
- Refrigerate for up to 1 week
Freezing Instructions
Place sliced bars in a single layer with parchment between layers in a freezer-safe container. Freeze for up to 3 months.
Thaw overnight in the refrigerator and bring to room temperature before serving.
Helpful Tips
✔ Use full-fat sweetened condensed milk — evaporated milk or fat-free versions won’t set properly.
✔ To double the recipe, bake in a 9×13-inch pan. Pre-bake crust for 18 minutes and bake filled bars for about 35 minutes, or until set.