Rhubarb Bars

With a buttery shortbread crust and tart filling, these easy rhubarb bars are the ones to make for people who love rhubarb.

By Mark Hinds  |  Updated April 20, 2022  |  0 Comments 

These rhubarb bars are set on a flakey shortbread crust with a slightly tart filling that uses a little honey to bring out the rhubarb’s natural flavors. This is the recipe for rhubarb bars for people who love rhubarb.

Delicious as a dessert, afternoon treat, or quick breakfast, the shortbread in these bars has warm, inviting flavors that compliment the rhubarb’s spunky tartness, which is mellowed by the sweet, complex flavors from the honey.

What sets this rhubarb bar recipe apart is how flavorful and straightforward the shortbread and rhubarb filling are to make.

What makes the recipe so simple is how the filling highlights the rhubarb without relying on weird food coloring tricks or overpowering everything with a ton of eggs and sugar. The filling is so simple it doesn’t even need to be cooked before getting baked.

A Simple Rhubarb Filling

Always an exciting choice for dessert recipes, rhubarb is one of those fascinating ingredients that is a vegetable in the plant world that is used as a fruit in culinary circles.

Famous for a crisp tartness that excels at providing contrasting flavors and textures to pastries, it’s a popular choice to use as the filling for pies, crisps, crumbles, and cakes.

A delicious spring dessert to make when the rhubarb starts to come up is this layered rhubarb cake.

Rhubarb Cut Up
The color in rhubarb ranges from off green to deep crimson.

One of the first vegetables harvested in the spring in temperate climates, it’s often among the first things to appear at farmers’ markets. Rhubarb season tends to run from early to late spring to mid-summer. While some people eat the stalks raw, a great option when it’s plentiful is to freeze bags of rhubarb to use throughout the year or turn it into jams and jellies. 

It’s worth noting if you’re working with fresh rhubarb, the leaves should never be eaten because they contain chemicals known to cause kidney stones and several other issues. (Wikipedia)

One of the reasons people freeze rhubarb is when it comes to baking; frozen rhubarb almost always works as well as fresh. We use fresh when it’s in season and frozen the rest of the year.

To highlight the rhubarb’s flavor, the filling for these bars is intentionally simple, with a bit of honey and sugar to bring some sweetness, some flour to act as a binder to hold everything together, and a tiny bit of lemon zest to brighten the overall flavor.

Rhubarb Bar Filling
The honey, sugar, and flour create a scrumptious filling.

The honey adds a lot to the filling bringing some complexity to the taste of the bars and letting us reduce the amount of sugar compared to similar recipes.

Baking a Delicious Shortbread Crust

The reason shortbread works so well as the crust for these bars is it’s strong enough to hold everything, enhances the bars’ taste, and is relatively simple to work with.

The best shortbread crusts are light and flaky and bring out the flavors in the filling while being delicious on their own.

We played with different combinations of flavors during our testing to find a shortbread with warm, inviting flavors on its own while adding depth and complexity to each bite.

Rhubarb Bar
The bars are delicious for dessert, as an afternoon treat, or a quick breakfast.

The final version uses a small amount of cinnamon along with a mix of vanilla and almond extracts to create a rich, complex shortbread with a crumbly texture that melts in your mouth. We worked hard on the shortbread for this recipe because it’s doing double duty, serving as the base and the topping.

We found that chilling the dough makes a big difference in how it bakes. Letting the shortbread chill for 20 to 30 minutes before baking helps the buttery shortbread crust hold its shape and produces a flakier shortbread with a superior texture to one baked right after the dough is mixed.

Tips for Better Rhubarb Bars

At first glance, these types of dessert bar recipes can seem a bit complex, with multiple components and things going in and out of the oven and fridge.

To help simplify things, we’ve designed this rhubarb bar recipe so you never have to work on two things at once.

Here are some additional tips for better rhubarb shortbread bars:

  • The recipe works with fresh or frozen rhubarb. If frozen is being used, it should be thawed and thoroughly drained before being mixed with the other filling ingredients. If the pieces are still wet after thawing, pat them dry with a paper towel.
  • A  tip for a better base is to keep the top of the crust even, which prevents the edges from overbaking or burning.
  • The bars are done when the shortbread on the top starts to turn a light golden brown. 
  • Letting the bars cool for at least 10 to 15 minutes after they come out of the oven helps the filling and the crust setup and holds everything together.
  • The bars should be stored in an airtight container and can be made a day or two ahead of time. If the bars are going to be eaten over more than a couple of days, they should be stored in the fridge.
Serving Bars
The tartness of the rhubarb compliments the sweetness in the shortbread

These bars are delicious all year long but are particularly good with fresh rhubarb in the spring. If the bars are being served warm, it’s nice to add a scoop of ice cream on the side.

A few of our favorite dishes to serve the bars with as a dessert are Smoked Duck Breasts, Grilled Lamb Chops, and Oven Roasted Chicken.

Rhubarb Bars

Rhubarb Bars

5 from 1 vote
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Prep Time: 20 minutes
Cook Time: 1 hour
Resting Time: 25 minutes
Total Time: 1 hour 30 minutes
Servings: 10

Ingredients

Shortbread Crust & Topping

  • 1 cup unsalted butter, room temperature (2 sticks)
  • 2 cups all-purpose flour
  • ¾ cup white sugar
  • ½ tsp cinnamon
  • 1 tsp vanilla extract
  • 1/2 tsp almond extract
  • 1/2 tsp kosher salt

Rhubarb Filling

  • 4 cups rhubarb, chopped
  • ¾ cup white sugar
  • ¼ cup all-purpose flour
  • 2 tbsp honey
  • 1 tbsp lemon juice
  • 1 tsp lemon zest
Makes: 11 x 7inch rectangle

Instructions

Shortbread Crust

  • Cream the butter and sugar in a mixer for 1 to 2 minutes until light and fluffy.
    1 cup unsalted butter, ¾ cup white sugar
  • Add vanilla and almond extract, flour, cinnamon, and salt. Continue mixing for 2 to 3 minutes until the dough has come together. Scrape the sides as necessary and continue mixing until it becomes pliant.
    2 cups all-purpose flour, ½ tsp cinnamon, 1 tsp vanilla extract, 1/2 tsp almond extract, 1/2 tsp kosher salt
  • Divide the dough into two bowls, with 2/3 set aside for the base and 1/3 for the topping.
  • Chill the dough for 20 to 30 minutes before prepping the pan. The dough can be chilled longer but may need to warm up for a few minutes before it’s workable.
  • To prepare the bottom crust, use an 11 by 7 or 9 by a 9-inch baking dish that is either sprayed with a nonstick spray or lined with parchment paper.
  • Using your hands, lightly press the dough into the bottom of the pan to form an even base layer. The dough should be around a 1/4 inch deep and should be as even as possible across the pan.
  • Par bake the crust in a preheated oven set to 350℉ (177℃) for 15 minutes.
  • Take the hot crust out and let it cool for 10 to 15 minutes.

Rhubarb Filling

  • Cut the rhubarb into bite-sized pieces.
    4 cups rhubarb
  • Mix the rhubarb, sugar, honey, lemon juice, and lemon zest.
    ¾ cup white sugar, ¼ cup all-purpose flour, 2 tbsp honey, 1 tbsp lemon juice, 1 tsp lemon zest
  • Set the mixture aside, giving it a good stir before adding it to the crust after it’s been baked and cooled.

Assembling the Bars

  • Spread the rhubarb mixture out across the baked crust. If the filling has excess liquid, use a slotted spoon to reduce the amount of liquid in the bars.
  • Break off small pieces of the remaining dough and spread them across the top of the filling. There should be gaps to let some of the filling show through. If the dough has been chilling for a long-time, it can be helpful to take it out of the fridge 5 minutes before this step.
  • Bake in a 350℉ (177℃) oven for 40 to 50 minutes. The bars are done when the shortbread on the top starts to turn a light golden brown.
  • Let the bars cool for 10 to 15 minutes before cutting them into squares. Giving them time to cool helps the filling set up and hold everything together.
Making this RecipeTag us on Instagram at @umami.site and hashtag it #umami_site
Nutrition
Calories: 406kcal | Carbohydrates: 57g | Protein: 4g | Fat: 19g | Saturated Fat: 12g | Polyunsaturated Fat: 1g | Monounsaturated Fat: 5g | Trans Fat: 1g | Cholesterol: 49mg | Sodium: 122mg | Potassium: 182mg | Fiber: 2g | Sugar: 34g | Vitamin A: 618IU | Vitamin C: 5mg | Calcium: 54mg | Iron: 1mg

Mark Hinds

A passionate writer, overly curious cook, and Umami's founder. Mark can often be found cooking for friends.

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Cuisine:  American|Midwestern| Technique: Baking 
Ingredients:
 Honey|Rhubarb
Misc: Bars|Breakfast|Brunch|Chef Desserts | Food|Recipes

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