Here’s a full, detailed brown sugar oat crumb bar recipe with clear directions. These are classic soft-but-sturdy bars with a buttery oat crumble and a sweet brown sugar center.
🍯 Brown Sugar Oat Crumb Bars
Makes: about 16 bars
Prep time: 15 minutes
Bake time: 30–35 minutes
🧺 Ingredients
For the oat crumb base & topping
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1½ cups old-fashioned rolled oats
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1½ cups all-purpose flour
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¾ cup light or dark brown sugar, packed
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½ teaspoon baking soda
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¼ teaspoon salt
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¾ cup (12 Tbsp) unsalted butter, melted and slightly cooled
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1 teaspoon vanilla extract
For the brown sugar filling
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¾ cup brown sugar, packed
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2 teaspoons all-purpose flour
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½ teaspoon ground cinnamon (optional but recommended)
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2 tablespoons unsalted butter, melted
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1 tablespoon milk or cream
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1 teaspoon vanilla extract
🔥 Directions
1. Preheat & prepare
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Preheat your oven to 350°F (175°C)
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Line an 8×8-inch baking pan with parchment paper, leaving overhang for easy removal
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Lightly grease if needed
2. Make the crumb mixture
In a large bowl, mix:
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Oats
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Flour
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Brown sugar
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Baking soda
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Salt
Add:
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Melted butter
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Vanilla extract
Stir until the mixture looks crumbly but holds together when pressed.
3. Press the base
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Set aside about 1 cup of the crumb mixture for the topping
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Press the remaining mixture firmly and evenly into the bottom of the prepared pan
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Use the bottom of a glass or measuring cup to pack it down well
4. Make the brown sugar filling
In a small bowl, combine:
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Brown sugar
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Flour
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Cinnamon
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Melted butter
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Milk
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Vanilla
Mix until smooth and thick.
5. Assemble
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Spread the brown sugar filling evenly over the pressed crust
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Sprinkle the reserved crumb mixture evenly on top (don’t press it down)
6. Bake
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Bake for 30–35 minutes, until:
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The top is golden brown
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The center is set (no jiggle)
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7. Cool & cut
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Let the bars cool completely in the pan (important for clean cuts)
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Lift out using parchment paper
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Cut into squares or rectangles
✨ Tips & Variations
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Chewier bars: Use dark brown sugar
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Extra flavor: Add ½ cup chopped pecans or walnuts to the crumb mixture
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Dessert-style: Drizzle with vanilla glaze once cooled
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Spiced version: Add nutmeg or cardamom to the filling