Amish Oatmeal Rhubarb Bars (with crumb topping)
Author: marilynpeight
These oatmeal rhubarb bars are easy to make and deliver a soft, oat-filled base topped with a sweet-tart rhubarb filling and a buttery crumb topping. This adapted Amish-style recipe fits an 8 x 8 inch pan and yields a tender, nicely textured bar with the ideal balance of sweet and tangy.
Rating: 4.53 from 106 votes
Summary
This simple recipe uses rolled oats, flour, brown sugar and butter for a crunchy-but-tender oatmeal crumb base and topping. The filling is a quick cooked rhubarb compote thickened with cornstarch and brightened with vanilla. The bars bake until the filling sets and the crumbs turn golden. They slice easily when completely cooled and store well at room temperature or frozen for longer keeping.
Details
- Prep time: 20 mins
- Cook time: 30 mins
- Servings: 9 (8 x 8 inch pan)
- Course: Dessert
- Cuisine: Amish-style
Equipment
- 8 x 8 inch baking dish (glass or metal)
- Mixing bowl
- 2-quart saucepan
- Measuring cups and spoons
- Spatula or spoon
- Parchment paper (optional, for easy removal)
Ingredients
- 1 cup old fashioned rolled oats
- 3/4 cup all-purpose flour
- 1/2 cup butter, softened
- 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 heaping tablespoon cornstarch
- 2 tablespoons water (to mix with cornstarch)
- 1/2 teaspoon vanilla extract
Instructions
- Preheat: Heat oven to 350°F (175°C).
- Make crumb mixture: In a medium mixing bowl combine the rolled oats, flour, softened butter, salt, baking soda and brown sugar. Mix until the ingredients form coarse crumbs. Reserve about 2/3 cup of the crumbs for the topping and press the remainder evenly into the bottom of a greased or parchment-lined 8 x 8 inch baking dish, pressing to remove cracks.
- Cook rhubarb filling: In a 2-quart saucepan combine the chopped rhubarb, granulated sugar and the cornstarch mixed with the 2 tablespoons of water. Stir over medium-high heat and bring to a simmer, stirring frequently. Cook 5–10 minutes until the rhubarb softens and the mixture becomes clear and slightly thickened. Remove from heat and stir in the vanilla. Let the filling cool about 10 minutes so it is warm, not hot.
- Assemble: Pour the warm rhubarb filling over the pressed oatmeal base and spread gently and evenly. Sprinkle the reserved 2/3 cup of oatmeal crumbs evenly over the top of the filling.
- Bake: Bake in the preheated oven 30–40 minutes, until the edges and bottom are golden and the filling and crumb topping have set. Allow the bars to cool completely in the pan before cutting so the filling firms up.
Notes & Tips
If you prefer a smoother filling, you can blend the cooked rhubarb after it has cooled slightly. That will create a jam-like consistency rather than distinct rhubarb pieces.
Use softened butter for the crumb mixture; if it’s not soft enough, a few short bursts in the microwave (10–15 seconds) can help—watch carefully to avoid melting. If the filling seems too thin after cooling, return it to low heat and stir in an additional 1/2 to 1 tablespoon cornstarch mixed with a small amount of water, cooking until clear and thickened.
If doubling the recipe for a 13 x 9 inch pan, reserve about 1 heaping cup of crumb topping instead of 2/3 cup. Lining the pan with parchment paper makes removing and slicing the bars easier.
Storage
Because the filling is cooked, these bars keep well. Store in an airtight container at room temperature up to 5 days, or wrap and freeze for several months. Thaw refrigerated before serving if frozen.
Step-by-step photos
If you try this recipe, please leave a comment to share how it turned out. Enjoy these tender, slightly tangy oatmeal rhubarb bars for dessert, tea time, or a sweet snack.