The Best Strawberry Rhubarb Squares


Summer means fresh rhubarb around my house and so I am sharing my must bake recipe for the best strawberry rhubarb squares I have. These squares start with a thick base that is pretty much a shortbread, then the base is topped with a strawberry rhubarb compote and finally a crumbly mixture of oats to top it all off. Baked to perfection then cooled before slicing into squares!

You can absolutely make these squares with just rhubarb but I find that by halving the rhubarb and adding in the same amount of strawberries you get the perfect sweet and sour combination.

What I love about these strawberry rhubarb squares is that they are not super sweet. I love the tartness from the rhubarb and the sweetness from the fresh strawberries. Even if you make them with rhubarb (or strawberry) only, they’re not too sweet. They do contain sugar, but not as much as some fruit bars do. I am obsessed with the flavor of these bars and I bet you will be too.

These squares are tart, sweet and full of flavor. The compote is thick enough that it doesn’t run out of the square when you cut them. It has the perfect amount of sugar, not too much but enough to enhance the fruit flavor. The squares hold their shape and integrity very well, which is an added bonus in my opinion.

This is one of those squares that you will find yourself going back to for more! They are irresistible and you’ll find yourself, knife in hand, cutting little pieces off, for just one more bite…i can see it now. Don’t be ashamed, I do the same thing..

What you need for the Best Strawberry Rhubarb Squares:

  • Rhubarb: Fresh is best. You will need about 4 or 5 large stalks. If you don’t grow it, most grocery stores carry bunches of rhubarb when in season.
  • Lemon (juice and zest): The lemon adds brightness to the flavor of the fruit and also helps the compote thicken with added pectin.
  • Sugar: adds just the right amount of sweetness to the compote, base and toppings.
  • Cornstarch: Used to thicken the compote.
  • All-purpose flour: Used in both the base and the crumble topping.
  • Baking Powder: It makes the base a bit thicker and softer (than a shortbread).
  • Butter: Used in both the topping and the crumble for texture and flavor.
  • Oats: Old-fashioned rolled oats are preferred to quick oats in this recipe. Quick oats tend to become mushy.
  • Vanilla Sugar: This isn’t a game changer if you don’t have it or can’t find it in your local store, BUT if you do have it, use it. It adds just a hint of vanilla to the perfect oat crumb topping.

How to make the Strawberry Rhubarb Filling:

Combine the compote ingredients in a saucepan (except the cornstarch) and cook on medium heat until bubbly then add the cornstarch and stir. Cook for 5 additional minutes to cook out the cornstarch and thicken the compote. Let cool for at least 5 minutes before adding it to the base layer.

Strawberry Rhubarb Squares

Delicious squares made with garden fresh rhubarb and strawberries with a shortbread crust and an oatmeal topping.1
Prep Time 15 minutes
Cook Time 25 minutes
Total Time 40 minutes
Course Baking, Dessert, desserts
Cuisine American
Servings 16 squares


  • 1 9X9" square baking pan


For the Base:

  • ½ cup granulated sugar
  • 2 cups all-purpose flour
  • 1 Tbsp baking powder
  • cup salted butter at room temperature
  • 1 lg egg

for the Rhubarb filling:

  • 2.0 cups rhubarb, diced
  • 1.5 cups Fresh strawberries, sliced into quarters
  • cup granulated sugar
  • 1 lg lemon, zest and juice
  • tsp cornstarch

For the Topping:

  • 1 cup Old Fashioned rolled oats (not quick oats)
  • ½ cup granulated sugar
  • 1 tsp Vanilla Sugar
  • ½ cup butter, melted


For the Base:

  • Preheat oven to 400℉
  • spray or grease a 9×9" square baking pan and set aside
  • Combine the ½ cup granulated sugar, 2 cups all-purpose flour, 1 Tbsp baking powder and a pinch of salt and then using your fingers add the softened butter and combine with the dry ingredients until there are no lumps. Add the egg and stir until a dough forms.
  • Cover the bottom of the prepared pan with the dough in an even, thick layer making sure to cover the entire bottom surface.

For the Strawberry Rhubarb filling:

  • In a small saucepan heat the 3.5 cups rhubarb and strawberries, ⅓ cup granulated sugar, lemon zest and lemon juice on medium heat until bubbly. Lower the heat and add the 2½ tsp cornstarchand stir well. Cook for 5 additional minutes until the mixture thickens.
  • Let the mixture cool at least 5 minutes until it is no longer hot. Pour the mixture over the base layer in the pan.

For the Topping:

  • Combine 1 cup Old Fashioned rolled oats (not quick oats), ½ cup granulated sugar, 1 tsp Vanilla Sugar and ½ cup butter, melted. Sprinkle the topping over the rhubarb layer.
  • Bake until the top is slightly golden about 20-25 minutes. Let cool completely before cutting. Enjoy!


If you find the top is not golden but the squares are bubbling, you can turn the oven to broil for a minute to brown the top,  just make sure to watch it carefully so it doesn’t burn the top.
Feel free to make this with just rhubarb or just strawberries, keeping the amount of fruit to 3.5 cups for one batch.  
Keyword rhubarb, squares, strawberry

Storing your Strawberry Rhubarb Squares:

Leave a comment

Your email address will not be published. Required fields are marked *

Recipe Rating

Previous Post Next Post