These Oatmeal Rhubarb were surprisingly easy to make and tasted absolutely delicious with the soft oatmeal base filled with a sweet and tangy rhubarb filling! This recipe for Oatmeal Rhubarb bars was adapted to fit an 8 by 8 inch pan, to make enough for a 13 by 9 inch pan simply hit the 2x button in the recipe card. These oatmeal rhubarb bars were inspired by an old order Amish cookbook, hence the name- Amish Oatmeal Rhubarb Bars. If you enjoy Amish baked goods, you may also enjoy Amish chocolate whoopie pies, Amish chocolate cake with peanut butter frosting, Amish chocolate chip cookies, or Amish coconut cream pie.
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Amish Oatmeal Rhubarb Bars (with crumb topping)
Equipment
- 8 by 8 inch baking dish (linked below)
- Mixing bowl (linked below)
- sauce pan (linked below)
- measuring cups (linked below)
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 brown sugar packed
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
Instructions
Preheat oven to 350 degrees.
- Combine the ingredients for the crumb topping in a medium sized mixing bowl, mixing until only coarse crumbs remain.
- Combine the chopped rhubarb, sugar, cornstarch and water in a 2 quart saucepan. Bring to a simmer over medium-high heat stirring frequently. Allow to cook for 5-10 minutes until the mixture is clear and the rhubarb has softened (keep stirring occasionally while cooking). Remove from heat and stir in vanilla extract, then allow to cool for 10 minutes, until no longer hot and the mixture has thickened a little more.
- Press all but 2/3 cup of the oatmeal crumbs into the bottom of a greased or parchment lined 8 by 8 inch baking dish, ensuring no cracks remain. Pour the warm rhubarb filling over the oatmeal crumb base, then sprinkle the remaining crumbs over top.
- Bake the rhubarb bars in the preheated oven for 30-40 minutes until golden on the bottom and the filling and crumb topping has set. Cool completely before cutting, then enjoy!
Notes
Equipment needed for these Amish Oatmeal Rhubarb Bars:
- 8 by 8 inch baking dish I prefer to use a glass baking dish for baking these rhubarb bars in. Using glass makes it more convenient for checking the sides and bottom of the bars for doneness.
- Mixing bowl Stainless steel mixing bowls are my favorite because of their durability and sturdiness.
- Saucepan You will need a 2 quart saucepan to cook the rhubarb filling in.
- Measuring cups I also prefer to use stainless steel measuring cups, an added bonus for me is that mine are dish washer friendly.
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Ingredients needed for these oatmeal rhubarb bars: Butter, water, brown sugar, baking soda, vanilla, cornstarch, rhubarb, sugar, rolled oats, flour and salt (not shown).
Step 1: Combine the ingredients for the oatmeal crumb base and crumb topping, until only coarse crumbs remain.
*Note
Be sure to use softened butter for the oatmeal crumb base to create a better crumb and also for easier mixing. If your butter is not yet soft enough to use, you can pop it in the microwave for around 10 seconds or more. Check the butter frequently while heating it, because you do not want it to melt.
Step 2: Combine all but the vanilla extract for the rhubarb filling in a medium sized saucepan. Stir frequently and cook over medium-high heat until the mixture is clear and the rhubarb has softened. Whisk in the vanilla extract and allow to cool for 10 minutes.
Note*
You will need to use a heaping tablespoon of cornstarch for the rhubarb filling. If the rhubarb filling is still too runny after it has cooled, you can return it to the heat and then add an additional 1/2-1 tablespoon of cornstarch mixed into water (be sure to mix with water before adding, to prevent lumps in the rhubarb filling). Allow to cook until clear, then remove from heat and cool again. If needed, additional vanilla can also be added after cooking, as cooking the vanilla can reduce the flavor.
Step 3: Press all but 2/3 cup of the oatmeal crumb into the bottom of an 8 by 8 inch pan, ensuring there are no cracks remaining.
Notes*
If doubling this recipe you will need to reserve around 1 heaping cup of the crumb topping.
I prefer to use parchment paper when baking bars like these oatmeal rhubarb bars, simply because it makes lifting the bars to cut them much easier!
Step 3 continued: Pour the slightly cooled rhubarb filling over the crumb topping. Spreading evenly over the oatmeal base with a spatula if needed.
Step 3 continued: Sprinkle the reserved 2/3 cup of oatmeal crumbs evenly over the top of the rhubarb filling.
Step 4: Bake the oatmeal rhubarb bars in the preheated oven for 30-40 minutes, or until golden on the edges and bottom, and the filling has set. Allow to cool before cutting.
Storage:
Because the rhubarb is cooked, the bars can be stored in an airtight container at room temperature for up to 5 days. The bars can also be wrapped and frozen for several months.
Feel free to pin this recipe for later and tag me on Instagram with a photo of your own creation. Thank you for your support!
Looks fantastic! Now to find rhubarb in the region i live in… Probably won’t happen but I’ll dream of tasting these! 🙂
I would love to make some for you!<3
I was looking for a simple recipe to use up some rhubarb and decided to try yours. I love it! I did cut back on the granulated sugar a little, as I like my rhubarb desserts on the tart side. The oatmeal crumb crust and topping were perfect. I will be making this again! Thank you!
I’m glad you enjoyed it!
Easy recipe! Came out perfectly. My rhubarb was green so I added 4 drops of red coloring to make it a pretty red. Will make this again for sure.
I’m glad it turned out good for you too! Sounds like a great tip if using green rhubarb.
My new favourite rhubarb desert! Easy and soooo delicious! Thanks
I’m glad you enjoy it too! It is one of our family favorites too.
Very easy recipe & delicious! Will definitely make again since my daughter grows rhubarb.
Wonderful! Glad you enjoyed the recipe too.
A wonderful recipe, but I think there’s a typo. I think you meant to say to press all but 1/3 of the crumb mixture (rather than 2/3s) in the bottom layer, as is typical in such recipes. It gives a bit more body to the square after baking. I added some sliced almonds to the remaining 1/3 and put a 1/2 t almond extract into the cooked rhubarb. It gave a nice depth of flavor.
Hi Kathleen, the recipe states to press all but 2/3 cup of crumbs onto the bottom of the pan. I find 2/3 cup or even a little less to be the perfect ratio of crumb on the bottom and crumb for the topping. Feel free to adjust to your preference though and I love the idea of adding almonds!
Kathleen, I think you just misread the recipe. It actually says to press all but 2/3 CUP into the bottom of the pan, not all but 2/3 of the mixture. Reserving 2/3 of a cup for the topping works well. Hope this helps!
I followed the recipe exactly and it was excellent! My husband told me not to lose this recipe, lol. Next time I might try adding a bit of cinnamon to the topping and see which way we prefer.
Wonderful! Cinnamon sounds like a great flavor addition with the oatmeal base.
Can you use frozen rhubarb and if yes, what adjustments are needed?
I haven’t tried it personally, but I believe it will work fine. I would pat the rhubarb dry with a towel once thawed, then add additional cornstarch to the sauce if it seems too wet.
It was delicious. Not too sweet not too tart!
I made these gluten free by using coconut flour, but used 2/3 cup of this flour as they aren’t equal in terms of substitutions. I also added about a half tsp. Cinnamon as someone else had suggested…good addition! These squares were very good. They were a little crumbly so shall have to practice with the ratio. Thank you for the recipe!
Thanks for sharing the gluten free tip! I’m glad you enjoyed them too.
These were easy and delicious! Thank you!
You are welcome, glad you enjoyed them too!
My husband wasn’t too excited about my making these bars, but after eating them decided I should make them as often as we have rhubarb. Since I was just given a bag full of rhubarb stalks, today I’m making a large batch of the rhubarb filling to put in portions in the freezer for use during the coming seasons. So glad you shared your recipe!
That’s great! I’m glad you were able to win him over with these bars!
These are soooo good! I added a few strawberries to the mixture for color and taste.
That sounds like a great tip! Glad you enjoyed them too.
This is a delicious recipe. The bottom in the middle did not get as firm as I would like. I wonder if using frozen rhubarb made a difference. It was so easy- I will make again. Thanks
I am glad you enjoyed it too! Yes, I do believe frozen rhubarb would be more watery than fresh rhubarb. You could try adding a little more cornstarch if using frozen rhubarb.
Absolutely delicious!! I added a few strawberries to the rhubarb filling, and it was perfect!
I’m glad you enjoyed them! Adding rhubarb sounds delicious!
I love this recipe! You should make it!
Excellent. I like the use of oatmeal in the rhubarb instead of just a shortbread base. Feels munchier.
I am glad you enjoyed it!
So good, and easy to make. I reduced to 1/2 cup sugar in the rhubarb filling and it was plenty sweet still. Will probably double the recipe next time as these will not last long.
I am glad you enjoyed them! Some rhubarb is more tart than other varieties, so that could account for the sweetness.
This looks so good! What a great combination of flavors!
Thanks for sharing! Does it keep long?
You are welcome. They keep for about a week in the refrigerator. I would recommend keeping them chilled for longer storage.
So delicious! Keeps the tart flavor of rhubarb perfectly without being over sweet!
I am glad you enjoy them too!