Description
These Rhubarb Oat Bars are the ultimate spring dessert! With a buttery oat crust, tangy rhubarb filling, and a golden cinnamon-sugar topping, they taste just like a rhubarb crumble—but in bar form! Perfect for potlucks, picnics, or just a cozy treat at home, these bars are rustic, easy to make, and totally irresistible. Let them cool completely for the best slice-and-serve texture!
Ingredients
Rhubarb Filling:
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4 cups chopped fresh rhubarb
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½ cup granulated sugar
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1 tbsp water
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A generous squeeze of fresh lemon juice
Oat Crust & Topping:
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1¼ cups all-purpose flour
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1¼ cups quick oats
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⅔ cup granulated sugar
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¼ tsp salt
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½ cup unsalted butter, melted
Topping:
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Cinnamon + sugar mix (for sprinkling)
Instructions
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Preheat and Prep:
Preheat oven to 350°F (175°C). Line a 9×9-inch baking pan with parchment paper, letting it hang over the sides for easy lifting. -
Make the Rhubarb Filling:
In a medium saucepan, combine chopped rhubarb, sugar, water, and lemon juice. Simmer over medium-low heat for about 10 minutes, stirring occasionally, until the rhubarb is softened but still slightly chunky. Set aside to cool. -
Prepare the Oat Base:
In a large mixing bowl, stir together the flour, oats, sugar, and salt. Add melted butter and mix until fully combined and crumbly. Remove ½ cup of this mixture and set aside for the topping. -
Press the Crust:
Press the remaining oat mixture firmly and evenly into the bottom of your prepared pan. -
Assemble the Bars:
Spread the cooked rhubarb mixture evenly over the crust. Sprinkle the reserved oat mixture over the top. Finish with a light dusting of cinnamon sugar. -
Bake:
Bake for 1 hour, until the top is golden brown and the rhubarb filling is bubbling. -
Cool and Slice:
Let the bars cool completely in the pan (at least 2 hours) before slicing into 16 squares.
Notes
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Frozen Rhubarb? You can use it—just thaw and drain before cooking to avoid extra moisture.
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Make it gluten-free by using a 1:1 gluten-free flour and certified gluten-free oats.
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For extra richness, swap granulated sugar with light brown sugar in the oat crust.
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Let the bars cool completely before cutting—this helps them firm up beautifully.
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These bars freeze well! Just wrap and store for up to 3 months.
Equipment
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9×9-inch baking pan
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Parchment paper
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Medium saucepan
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Mixing bowls
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Measuring cups & spoons
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Spatula or spoon
- Prep Time: 20 minutes
- Cook Time: 1 hour
- Category: Dessert
- Method: Baking
- Cuisine: American
Nutrition
- Serving Size: 1 square
- Calories: 185 kcal
- Sugar: 15g
- Sodium: 40mg
- Fat: 7g
- Saturated Fat: 4g
- Unsaturated Fat: 3g
- Trans Fat: 0g
- Carbohydrates: 29g
- Fiber: 1.5g
- Protein: 2g
- Cholesterol: 15mg
Keywords: Rhubarb bars, Rhubarb oat bars, Rhubarb dessert, Spring desserts, Rhubarb recipes