Rhubarb Oat Bars

These rhubarb oat bars are perfect for when you want a tasty treat for a crowd.

rhubarb oat bar

Serve them warm, right out of the oven with a scoop of vanilla ice cream. They’ll be soft and crumbly, so serve on a plate with a fork.

To serve them as grab and hold bars, let the pan chill so the dough has a chance to set up and hold its shape. Then cut into bars or squares however big or small you’d like ’em. Perfect for summer barbecue parties and potlucks.

rhubarb oat bar

Print Recipe
5 from 2 votes

Rhubarb Oat Bars


  • Filling
  • 3 cups Rhubarb chopped
  • 1 tbsp Lemon Juice
  • 1/2 cup Sugar
  • 2 tbsp Cornstarch
  • 1 tsp Cinnamon
  • Crust
  • 1 cup Whole Wheat Flour
  • 1 cup All-purpose Flour
  • cup Large Flaked Oats
  • 2/3 cup Brown Sugar
  • ½ tsp Baking powder
  • ¼ tsp Salt
  • 1 tsp Cinnamon
  • 1 cup Butter melted
  • ¾ cup Icing Sugar
  • 1- 2 tbsp Milk


  • Filling
  • In saucepan, cook rhubarb and lemon juice, stirring occasionally, until fruit is tender (8 to 12 minutes). The rhubarb should release enough moisture to the pan, if needed add 1 to 2 tablespoons water to pot.
  • Mix sugar, cornstarch and cinnamon. Stir into rhubarb.
  • Continue cooking, stirring constantly, until mixture boils and thickens.
  • Remove from heat and set aside.
  • Crust
  • Preheat oven to 350°F (180°C).
  • Combine flours, oats, brown sugar, baking powder, salt and cinnamon.
  • Add melted butter and mix until no dry spots remain and mixture resembles coarse crumbs.
  • Press 2/3 or crumbs into bottom of 9x13 inch (23x33 cm) pan.
  • Spread filling evenly over crust. Sprinkle reserved crumbs on top and press down lightly.
  • Bake until golden brown, about 35 to 40 minutes.
  • Remove from oven and set pan on wire rack to cool completely.
  • Mix icing sugar and just enough milk for the glaze to flow easily.
  • Drizzle mixture over the cooled bars, before cutting.
  • Serve warm on a plate with a fork for soft, crumbly bars. For more solid bars you can hold in your hands, let bars set for at least two hours before cutting and serving.


Yield Makes 18-24 bars
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Want to learn more about rhubarb and a list to other rhubarb recipes, check out 7 Things You Need to Know About Rhubarb.

Sign up to get articles by Getty delivered to your inbox. You’ll get recipes, practical tips and great food information like this. Getty is a Professional Home Economist,  speaker and writer putting good food on tables and agendas.  She is the author of Manitoba’s best-selling Prairie Fruit Cookbook, Founder of Fruit Share, a mom and veggie gardener.

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