These Amish oatmeal rhubarb bars are a comforting homemade dessert featuring a buttery oat crust, a sweet and tangy rhubarb filling, and a crumbly topping. They are simple to prepare and perfect for spring when rhubarb is at its peak. Each bite offers a balance of textures, from soft filling to slightly crisp topping.
Why You’ll Love This Recipe
This recipe is wonderfully straightforward and uses basic pantry ingredients along with fresh rhubarb. The same mixture is used for both the crust and topping, making preparation easier and quicker. The bars have a perfect balance of sweetness and tartness, and they slice neatly once cooled. They are ideal for family desserts, snacks, or even sharing at gatherings.
Ingredients
(Tip: You’ll find the full list of ingredients and measurements in the recipe card below.)
For the crumb base and topping:
1 cup old fashioned rolled oats
3/4 cup all-purpose flour
1/2 cup softened butter
1/8 teaspoon salt
1/8 teaspoon baking soda
1/2 cup packed brown sugar
For the rhubarb filling:
1 1/2 cups chopped rhubarb
3/4 cup granulated sugar
1 tablespoon cornstarch (heaping)
2 tablespoons water
1/2 teaspoon vanilla extract
Directions
Preheat the oven to 350°F and prepare an 8 x 8-inch baking dish by greasing it or lining it with parchment paper.
In a mixing bowl, combine the oats, flour, butter, salt, baking soda, and brown sugar. Mix until the texture becomes crumbly and resembles coarse crumbs.
In a saucepan over medium-high heat, combine the chopped rhubarb, granulated sugar, cornstarch, and water. Cook while stirring until the mixture begins to simmer. Continue cooking for about 5 to 10 minutes, until the rhubarb softens and the mixture thickens and becomes glossy.
Remove from heat and stir in the vanilla extract. Allow the filling to cool for about 10 minutes.
Reserve about 2/3 cup of the crumb mixture for the topping. Press the remaining mixture firmly into the bottom of the prepared baking dish to form an even crust.
Spread the rhubarb filling evenly over the crust. Sprinkle the reserved crumb mixture over the top.
Bake for 30 to 40 minutes, until the top is lightly golden and the filling is set. Allow the bars to cool completely before cutting into squares.
Servings and timing
This recipe yields 9 bars.
Prep time: 20 minutes
Cook time: 30 to 40 minutes
Total time: about 50 to 60 minutes, plus cooling time
Variations
You can customize these bars in several ways. Add a pinch of cinnamon or nutmeg to the crumb mixture for extra warmth. Mix strawberries with the rhubarb for a sweeter filling. For a crunchier topping, add a small handful of chopped nuts such as almonds or walnuts. You can also increase the vanilla slightly for a richer flavor.
Storage/Reheating
Store the bars in an airtight container at room temperature for up to 5 days. If you prefer longer storage, place them in the refrigerator for up to a week or freeze them for up to 2 months.
To reheat, warm individual bars in the microwave for a few seconds until just heated through. For best texture, allow refrigerated or frozen bars to come to room temperature before serving.
FAQs
Can I use frozen rhubarb?
Yes, just thaw it completely and drain any excess liquid before using.
Do I need to peel rhubarb?
No, rhubarb does not require peeling. Simply wash and chop it.
Can I substitute quick oats?
Yes, but the texture will be softer compared to using old fashioned oats.
Why is my filling too runny?
It may not have cooked long enough or needs more time to cool and set.
Can I make these ahead of time?
Yes, they actually slice better after resting, making them ideal for preparing in advance.
What pan size should I use?
An 8 x 8-inch baking dish works best for this recipe.
Can I double the recipe?
Yes, use a 13 x 9-inch pan and adjust baking time slightly.
How do I know when they are done?
The top should be golden and the filling should appear thick and set.
Can I reduce the sugar?
Yes, but it will make the bars more tart.
Should I refrigerate leftovers?
It is optional, but recommended if your kitchen is warm.
Conclusion
These Amish oatmeal rhubarb bars are a delightful blend of buttery, crumbly texture and bright, tangy filling. They are easy to prepare and perfect for both everyday treats and special occasions. Once you try them, they are sure to become a favorite addition to your dessert collection.
