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Lemon Oatmeal Crumble Bars Recipe

4.5 from 90 reviews

Delightfully tangy and sweet, these Lemon Oatmeal Crumble Bars feature a buttery oat crumble crust and topping encasing a luscious lemon custard filling. Perfectly baked to a golden finish, these bars combine zesty lemon flavor with hearty oats for a refreshing dessert or snack.

Ingredients

Scale

For the Crust & Topping:

  • 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)

For the Lemon Filling:

  • 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

  1. Prepare the oven and pan: Preheat your oven to 350°F (177°C). Line an 8-inch square baking pan with parchment paper to ensure easy removal of the bars once baked.
  2. Make the crust and topping: Using a handheld or stand mixer with the paddle attachment, cream the softened butter and brown sugar together on medium-high speed until fully combined, about 1 minute. Scrape down the bowl sides, add the vanilla extract, and beat again for 30 seconds until incorporated. Next, add the flour, baking powder, salt, and oats; mix on medium speed until the mixture is crumbly and dry, forming between 3 to 3.5 cups of mixture.
  3. Form the crust: Press slightly more than half of the crumble mixture evenly into the bottom of the prepared baking pan to create the crust. Bake this crust layer for 12 minutes, then remove it from the oven.
  4. Make the lemon filling: In a medium bowl, whisk together the sweetened condensed milk, lemon juice, and lemon zest until smooth and thickened slightly.
  5. Assemble the bars: While the crust is still warm, pour the lemon filling evenly over it. Then sprinkle the remaining crumble mixture evenly on top of the lemon filling.
  6. Bake: Return the pan to the oven and bake for an additional 22–25 minutes or until the edges are lightly golden and the center has set without wobbling. Take care to avoid over-baking to maintain a soft texture.
  7. Cool and cut: Remove the bars from the oven and let them cool completely on a wire rack. Use the parchment paper to lift them out of the pan, then cut into squares as desired.
  8. Storage: Store any leftover bars at room temperature for up to 2 days or refrigerate them for up to 1 week in an airtight container to maintain freshness.

Notes

  • Use fresh lemons for the best citrus flavor and vibrant zest.
  • Pressing the crust firmly ensures a sturdy base for the filling.
  • Avoid over-baking to keep the lemon filling creamy and smooth.
  • Bars can be refrigerated to extend shelf life and served chilled or at room temperature.
  • Substitute oats with gluten-free oats to make this recipe gluten-free.

Keywords: Lemon bars, oatmeal crumble bars, lemon dessert, lemon oat bars, sweetened condensed milk dessert, crumble topping, citrus bars