Easy Rhubarb Custard Bars

These easy rhubarb custard bars are the perfect dessert for rhubarb season. A sweet shortbread crust is topped with a delicious rhubarb custard filling and baked to perfection, making the perfect rhubarb bars. These bars bake up quickly and are perfect for a summer picnic or BBQ. These rhubarb bars can also be made gluten free by replacing the all purpose flour in the crust with gluten-free flour, so even the gluten free rhubarb lover can enjoy it. This easy dessert is one your family will love and request over and over again.
Rhubarb is traditionally called the pie plant, because it’s great for making pie and all kinds of delicious treats. Rhubarb is a perennial and one of the earliest things you can harvest from your garden or purchase from farmers market in the spring. It grows especially well in northern climates. Kept picked, rhubarb will produce a nice harvest all summer long. If it’s not regularly enough, or if it gets too hot, it will send up a seed stock in the middle. This can be broken off, and that will encourage the plant to keep producing.
To harvest rhubarb, it’s best to pull up on the stock so they detach themselves from the crown of the plant that is underground. This encourages the plant to continue producing rhubarb stalks, which is exaclty what you want. If you cut the rhubarb stalks down closer to the ground, the plant will think that the stalk is still there because the bottom piece of it is still connected to the crown of the plant. When this happens the crown will not produce another stalk in that same location. Be sure to always discard the leaves of the rhubarb, as they can be toxic to humans and animals.
Preserving Rhubarb
If you want to be able to make this recipe even when rhubarb isn’t in season, then you’ll need to preserve some rhubarb. The best way to preserve rhubarb for use in recipes like this is to freeze it. I like to chop it up in the food processor and place it in a quart ziplock freezer bag. It will keep in the freezer for up to a year. I suggest thawing it completely and draining any excess water off before using it to make these rhubarb custard bars.

Why You’ll Love This Recipe
- Perfect combination of tart and sweet, the tart rhubarb is perfectly offset by the shortbread crust and sweet custard filling.
- Easy to pack for lunches or picnics.
- A great way to use up rhubarb in the summer.
- Similar to lemon bars with the wonderful texture of rhubarb.
- These dessert bars are easy to make gluten free.
- You can also cut this recipe in half and put it in a square baking pan.
Variations
If you aren’t a big fan of rhubarb, or it’s not in season, just make these same bars with another fruit of your choice. Some of my favorite fruits to use in place of fresh rhubarb are:
- Blueberries
- Strawberries (you could make strawberry rhubarb bars by adding both strawberries and rhubarb)
- Apples
- Fresh raspberries
Ingredients
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Tools
How to Make These Easy Rhubarb Custard Bars
Preheat your oven temperature to 350 degrees.
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Combine crust ingredients together in a 9 x 13 pan using a fork and your hands to thoroughly mix them together. Then press into the bottom of the pan.

Bake for 20 minutes or until crust starts to turn golden brown on the edges.
Meanwhile, in a medium sized mixing bowl add eggs, sugar, flour and lemon juice and stir well with a whisk.

Chop the rhubarb and add to the filling mixture, stirring gently.

When the crust is done baking, pour the rhubarb mixture on top of the hot crust.

Return to the oven and bake for 20-30 minutes or until the center of the bars is set.
Allow to cool completely before serving.
Cut into bars and serve.

Leftover bars can be stored in an airtight container for up to a week in the refrigerator, or frozen for up to three months.
Tips
- Save on dishes by just mixing up the shortbread crust right in the baking pan
- Make this delicious dessert with whatever fruit you have on hand
- Individually wrap these bars in parchment paper and tie with a string for a cute presentation at a picnic
More Recipes Like This

Easy Rhubarb Custard Bars
Ingredients
Crust Ingredients
- 2 cups all purpose or gluten free flour
- 1/2 cup sugar
- 1 cup butter softened
Filling Ingredients
- 4 eggs
- 1 3/4 cups sugar
- 1/4 cup all purpose or gluten free flour
- 1 Tbl. lemon juice
- 4 cups diced rhubarb
Instructions
- Preheat your oven temperature to 350 degrees.
- Combine crust ingredients together in a 9 x 13 pan using a fork and your hands to thoroughly mix them together. Then press into the bottom of the pan.
- Bake for 20 minutes or until crust starts to turn golden brown on the edges.
- Meanwhile, in a medium sized mixing bowl add eggs, sugar, flour and lemon juice and stir well with a whisk.
- Chop the rhubarb and add to the filling mixture, stirring gently.
- When the crust is done baking, pour the rhubarb mixture on top of the hot crust.
- Return to the oven and bake for 20-30 minutes or until the center of the bars is set.
- Allow to cool completely before serving.
- Cut into bars and serve.
- Leftover bars can be stored in an airtight container for up to a week in the refrigerator, or frozen for up to three months.
Notes
- Save on dishes by just mixing up the shortbread crust right in the baking pan
- Make this delicious dessert with whatever fruit you have on hand
- Individually wrap these bars in parchment paper and tie with a string for a cute presentation at a picnic