Rhubarb Blueberry Oatmeal Bars

Blueberry Rhubarb Oatmeal Bars
Blueberry Rhubarb Oatmeal Bars
Blueberry Rhubarb Oatmeal Bars

The blueberry squares at Starbucks are the inspiration for these Rhubarb Blueberry Oatmeal Bars. I had one of those a while ago, and it was delicious. And I knew I had to make a homemade version. Blueberries are in season now, and we had a bunch of the sweet, juicy berries.  And we also had rhubarb, so I decided to add that, too. Injecting a little bit of tartness was a good idea, because blueberries and rhubarb were perfect together in these squares.

Can we call these semi healthy?  Yes, there's butter and sugar. But they are made with fruit, and there are oats in there, too. But who am I fooling. These are a treat, no doubt about it. A delicious treat of blueberry rhubarb goodness between buttery oatmeal crispness. And we all need a treat sometimes. Life is about balance, and treats are part of that.

The best way to eat these fresh juicy blueberries, is of course, just straight up. At least for me. I can just plow through a bowl of these like they were peanuts. But I also like to showcase these luscious local berries in a recipe now and then, too. Like this Finnish Blueberry Pie, or Blueberry French Toast Casserole, or even in a savory dish like Blueberry Sourdough Sausage Stuffing, for your next holiday feast. You can even use these beauties in a cocktail! Try a Blueberry Ginger Martini, you won't regret it.

So yes, obviously I'm a big fan of blueberries. I'm a big fan of eating local. And I live in a province where cultivated blueberries are a major crop. So getting my order of local, fresh, organic blueberries each summer is something that I always look forward to. And the bonus is, blueberries freeze very well. So I get a large amount, and freeze them. Then I can have blueberries every day in my morning smoothie, all winter long.

These delicious blueberry oatmeal bars should be cooled completely, allowing them to set, before slicing.

Blueberry Rhubarb Bars
Blueberry Rhubarb Bars

Rhubarb Blueberry Oatmeal Bars

Prep Time: 30 minutes

Cook Time: 45 minutes

Total Time: 1 hour, 15 minutes

Yield: 24 bars

Serving Size: 1 bar

Rhubarb Blueberry Oatmeal Bars


  • 3 cups fresh blueberries
  • 3 cups rhubarb, cut into 1 inch pieces
  • juice of one lemon
  • 1 cup sugar
  • 4 tbsp cornstarch
  • 2.5 cups quick cooking oats
  • 1 cup all purpose flour
  • 1 cup brown sugar, packed
  • 1/2 tsp baking soda
  • 1/4 tsp salt
  • 1 cup cold butter, cut into cubes


  1. Put blueberries and rhubarb chunks Into a large, stainless steel pot, over medium heat
  2. Cook, stirring occasionally, until rhubarb is softened.
  3. In a small bowl, whisk sugar and cornstarch together
  4. Add to fruit mixture, stirring constantly until thickened and smooth.
  5. Remove from heat.
  6. Heat oven to 350° Prepare a 9 x 13 baking pan by spraying with cooking oil, or, lining with parchment paper.
  7. In a bowl, combine oats, flour, brown sugar, baking soda and salt.
  8. Using a pastry blender to cut butter into flour mixture until it resembles course crumbs
  9. Press half the flour mixture into prepared pan to form crust
  10. Spread blueberry rhubarb mixture over the bottom crust
  11. Spread remaining flour mixture over the fruit layer, pressing lightly
  12. Bake in center of oven until golden, about 45 minutes
  13. Cool completely on a wire rack before slicing into 24 squares


Don't have fresh blueberries? An equal quantity of thawed frozen blueberries (unsweetened) will work fine in this recipe.


Rhubarb Blueberry Oatmeal Bars
Rhubarb Blueberry Oatmeal Bars


14 thoughts on “Rhubarb Blueberry Oatmeal Bars

  1. I must make these. My mouth is watering. Also the photography is so good, it’s not easy to take good food pics and you are excelling.

    1. Thanks Dina! These really are delicious. And thanks for your kind words. I love the photography aspect of blogging, and I’m always learning and striving to improve. So those words are very encouraging. 🙂

  2. I hardly make squares, but now that I’ve seen these beauties I am excited to make some. Love the flavors! I agree, life is about balance, in life as in food.

    1. Justine, yes, they are an amazing combo! I love how the rhubarb tempers the super sweet blueberries. I can think of a lot of other ways to use those two besides these squares. Enjoy your weekend, too!

  3. I have a TON of fresh rhubarb and a box of blueberries, and now I know exactly what to bake with them! Loving the combination of these fruits plus the oats!

    1. Hi Jessica! Isn’t it great having all this freshness to deal with? I’m constantly looking for ideas to use all the fresh produce. (not complaining :-))

  4. Looks delicious! I think your homemade version is much better and fresher than Starbucks! We love our blueberries too! Me and my son and easily chomp down a few pounds! Thanks for sharing! And I am going to buy some more blueberries! I love to freeze them at the end of summer so I can enjoy them during the winter months too!

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