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Grandma Valita's Rhubarb Bars

Grandma Valita's Rhubarb Bars

  • Author: Sarah Marx Feldner
  • Prep Time: 20
  • Cook Time: 30
  • Total Time: 50 minutes
  • Category: Bars
  • Method: Baking
  • Cuisine: American


Makes ~16 bars, depending on how you slice them.

If enjoying over the course of more than a day or two, store in the refrigerator.



For the filling:

  • 1 1/2 cups granulated sugar (300 g)
  • 2 TB cornstarch (16 g)
  • 3 cups chopped rhubarb (from about 1 lb)
  • 1/4 cup water
  • 1 tsp vanilla

For the bars:

  • 1 1/2 cups quick oats (120 g)
  • 1 cup packed light brown sugar (213 g)
  • 1 1/2 cups all-purpose flour (180 g)
  • 1/2 cup chopped walnuts (56 g) (optional, see note)
  • 1/2 tsp baking soda
  • 1/2 tsp fine-grain salt (like table or sea salt)
  • 1 cup cold, unsalted butter (2 sticks, 8 oz)


Preheat oven to 375F degrees

Butter a 9 x 13 pan and line the bottom with parchment

For the filling:

  1. In a medium saucepan, whisk together the cornstarch and sugar. Add in the rhubarb and water and stir until everything is well combined. Over medium heat, cook until the sugar is melted and soupy. Increase heat to medium-high and bring to a full boil. Stirring constantly, boil 1 - 2 minutes, until the the sauce is thickened, no longer cloudy, and the rhubarb has broken down. (The total time for making the filling is ~10 minutes.) Remove from the heat and stir in the vanilla. Set the filling aside while you make the bars.

For the bars:

  1. In a large bowl, stir together all the ingredients except the butter. Rub in the cold butter with your fingers, a pastry blender, or a fork until the mixture looks pebbly.
  2. To assemble, reserve 1 cup of the oat-flour mixture. Press the remaining mixture into the prepared pan. Top with the rhubarb filling (it will still be warm) and spread evenly. Then sprinkle with the reserved oat-flour mixture.
  3. Bake 30-35 minutes, until golden brown and the edges are bubbling. Let cool completely before slicing. These bars are equally delicious at room temperature or cold out of the fridge.


  • I usually omit any nut called for in a baked good, 🤷 but walnuts really do pair beautifully with rhubarb. So for this recipe, I like to chop the walnuts extra, extra fine (so you get the flavor, but not the crunchy texture). And if I'm feeling especially fancy, I'll lightly toast the walnuts ahead of time.

Keywords: Rhubarb, Rhubarb Bars, Rhubarb Recipes, Old-Fashioned Recipes, Grandma Recipes, Spring Recipes, Summer Recipes