Rhubarb crumble bars that are super easy to make and a perfectly sweet, delicious summer treat! A tart, rhubarb filling sandwiched between a buttery shortbread base and a nutty crumble topping.
Just like my peach crumble bars , these delicious rhubarb bars with a crumble topping are vibrant in color and flavor, and taste like summer! And ridiculously easy to make too.
I love making the most of rhubarb during the very short rhubarb season in Canada. Strawberry rhubarb pie , rhubarb syrup , rhubarb lemonade , rhubarb margarita etc. are some of my favorites things to make with that supply of fresh rhubarb.
These rhubarb crumble bars have also been making an appearance in my kitchen repeatedly over the last month, and summer has only just officially begun!
But the great thing is that you can easily adapt these dessert bars into strawberry rhubarb bars with a crumble topping, to make use of all the gorgeous strawberries available in summer as well. These are such fantastic fruit desserts to enjoy all summer long.
These rhubarb bars start with a homemade rhubarb filling that is similar to a jam. I add some apple to the filling, purely to help thicken the filling properly to a jam-like consistency WITHOUT adding too much sugar.
This jam is then spread between a buttery shortbread layer and a crumb topping that is made with the SAME dough! So you end up with a delightfully buttery, tart rhubarb bar that has just the right amount of sweetness!
Ingredients
Rhubarb filling
Rhubarb
Fresh rhubarb is obviously the most important ingredient for rhubarb bars! I have made this recipe with beautifully red rhubarb stalks as well as green stalks, and ones in between as well. When choosing your fresh rhubarb for this recipe, don’t worry about the color of rhubarb or the quality of the rhubarb. Some blemishes are absolutely fine as they can be removed prior to cooking.
The red rhubarb stalks will obviously produce a prettier color, but there won’t be a difference in taste. If you like though, you can substitute some of the rhubarb with some strawberries for flavor and color.
Green apple
You CAN leave this out if you like. But I LOVE the additional tart flavor and jammy texture that apples add to the filling.
Sugar
I use white sugar so that the flavor of rhubarb can shine through. I prefer not to use brown sugar for this recipe.
Lemon juice
The fruity acidity from lemon juice will brighten up the filling flavor for a more summery rhubarb bar!
Shortbread base and topping
Butter
I use unsalted butter, so that I can control the salt level in my shortbread base. You can use salted butter, but be mindful to reduce the amount of salt you add to the recipe. There is no need to use frozen butter or cold butter in this recipe, as we will be using softened butter instead.
Egg
I add an egg to this recipe to act as a binder. As a result, the shortbread base isn’t too crumbly and will hold together very well.
Sugar
I use caster sugar (white), so that the sugar will dissolve more readily in the dough, but you can use granulated sugar as well.
Flour
All purpose flour is ideal for this rhubarb recipe. You can use cake flour if you like and if that’s all you have. But avoid using bread flour, since the high gluten content in bread flour can make the shortbread tough.
Flavoring
Vanilla and salt are the only flavoring that I add to the shortbread base. You could also add a little almond extract if you like. Personally, I do not like almond extract however.
Optional topping ideas
The shortbread dough for the topping can be mixed with chopped nuts or other additions to make the crumble topping for your rhubarb crumble bars more interesting. This is optional though. Here are some ideas,
- Almond slices
- Walnuts
- Pecans
- Coconut (desiccated or flakes)
- Cashew nuts
- Oats
- Puffed quinoa
Recipe variations
- To make strawberry rhubarb bars – You can replace 50% of the rhubarb with strawberries to make the filling. If you’re using ready-made jam, use ½ rhubarb jam and ½ strawberry jam .
- To make strawberry crumble bars – Replace the rhubarb topping with this homemade strawberry jam instead.
- Vegan options – Replace the butter with a vegan butter (not margarine) and instead of the egg, use about ¼ cup of plant-based milk to bring the dough together.
Can I make these rhubarb bars ahead of time?
Yes! The jam can be made weeks in advance, but you have to freeze the rhubarb jam until you need it. Then just thaw it before you spread it on top of the shortbread layer.
The dough can also be made ahead of time, but it’s so easy and quick to assemble, that I never really bother making it ahead of time. But if you like, here is how you can store the dough if you don’t want to make the bars right away.
Make the dough and flatten it into a disc. Wrap and store in the fridge for up to 2 days. When you’re ready to use it, let it soften slightly, and then remove about ¼ if the dough and set that aside for the topping. Then proceed with the recipe instructions for assembly.
My preference however is to make the rhubarb bars, bake them, and then store those for later instead!
Storage instructions
Once the bars have cooled down, cut them into squares or bars (however you like). I usually cut them into 4 x 4 pieces (16 squares). Make sure to use a sharp knife to get those clean edges. Store the bars in an air-tight container.
- Room temperature – about 2 days
- Fridge – about 1 week
- Freezer – about 2 months. If you’re storing them in the freezer, make sure to separate stacked bars with parchment paper to prevent them from sticking to each other. I also highly recommend that you wrap them in foil before storing it in an air-tight container. I find that this practice reduces the buttery shortbread from absorbing other smells from the freezer.
Tips for perfect rhubarb bars
- You don’t HAVE to make the rhubarb topping in advance! Once you make the topping, spread it out on a quarter sheet pan and place it in the freezer or fridge to cool it down faster.
- You can use red OR green rhubarb. It’s also a great recipe to use up rhubarb that’s a little bruised or wilted. You can also use frozen rhubarb to make the filling, if fresh rhubarb isn’t available.
- Make sure to use a kitchen scale for the ingredients (especially for the shortbread dough). Adding too much flour can result in a dry and crumbly shortbread crust.
Recipe
Easy Rhubarb Crumble Bars
Ingredients
Rhubarb filling
- 450 g rhubarb cut into 1 inch pieces
- 150 g white sugar
- 65 g green apple, grated about 1 medium apple
- 1.5 tbsp lemon juice
- 4 tbsp water
- Pinch sea salt
Shortbread dough (base and topping)
- 300 g AP flour (spooned and leveled for cup measurements)
- 150 g white sugar
- ¼ tsp sea salt
- 226 g butter 2 sticks
- 1 large egg
- 1 tsp vanilla extract
- 3 tbsp sliced almonds or rolled oats optional
Instructions
Rhubarb filling (makes about1½cups)
- Place the rhubarb, sugar, apple, lemon juice, water, and salt in a saucepan (I use a 5 qt / 1 L pot for 1 batch). Mix well to combine. 450 g rhubarb, 150 g white sugar, 65 g green apple, grated, 1.5 tbsp lemon juice, 4 tbsp water, Pinch sea salt
- Place the pot over medium-high heat and cook until the mix comes to a boil. Stir frequently while cooking. This should take about 10 minutes.
- Reduce the heat to medium / medium-low and continue to cook the mixture while stirring frequently. The mixture may start to bubble, so be careful!
- Cook until the mixture starts to thicken and it looks like apple butter. This can take a further 20 - 30 minutes.
- Once thickened, remove from the heat and transfer the filling into a bowl. Let it cool down to room temperature. Cover and let it chill in the fridge until the next day if needed, but the filling can be used at room temperature (or slightly warmer as well).
Shortbread dough
- Make sure the butter is soft and at room temperature. You can use cold butter as well, but it will be harder to mix. If the butter is hard and not easily pressed, place the butter in a warm area until it’s soft (or microwave on low power). Do not let it melt. 226 g butter
- In a large bowl, mix the flour, sugar and salt. 300 g AP flour, 150 g white sugar, ¼ tsp sea salt
- Add the butter, egg, and vanilla. 226 g butter, 1 large egg, 1 tsp vanilla extract
- Using a spatula, mix the butter, egg and flour mix together. You can also use your hands to mix the dough.
- Make sure the butter and egg are mixed through the flour uniformly and forms a soft dough.
- Divide the dough into two pieces - ¾ of the dough and a smaller ¼ of the dough. Cover the dough and let it rest while you prepare the baking pan.
Assembly and baking
- Preheat the oven to 350°F / 180°C.
- Butter and line a 9 inch square pan with parchment paper.
- Take the larger portion of shortbread dough (¾ portion), and press it into the bottom of the baking pan. Make sure the dough is pressed into a flat, even layer. Use a flat surface like a spatula or the bottom of a glass to evenly press the dough into the base.
- Spread about 1 cup of the cooled rhubarb filling over the shortbread layer.
- OPTIONAL - add the almond or oats to the ¼ portion of the dough. Break up the dough into smaller pieces and mix it with the nuts / oats. 3 tbsp sliced almonds or rolled oats
- Take smaller pieces of the dough and flatten them slightly. Place these flattened dough pieces on top of the rhubarb filling layer. You can place enough to cover the whole rhubarb filling or leave some gaps to have the filling peaking through.
- Transfer the baking pan into the preheated oven and bake for about 40 minutes, rotating the pan once halfway through the baking time. Remove the pan from the oven when there is some browning on the surface.
- Let the bars cool down to room temperature. Preferably let it chill for a few hours in the fridge to make it easier to cut them into bars.
- Remove the rhubarb bars from the pan and cut into squares or bars. I cut them into 16 squares.
- Store the bars in an airtight container for up to 1 week in the fridge.
Notes
Storage instructions
Nutrition
Recipe from The Flavor Bender by Dini Kodippili
Easy Rhubarb Crumble Bars https://www.theflavorbender.com/easy-rhubarb-crumble-bars-recipe/
