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This buttery rhubarb custard bar recipe creates the perfect spring dessert with its shortbread base and tangy fruit filling. Each bite delivers a delightful contrast between the crisp crust and silky smooth custard, making it impossible to stop at just one square.
I discovered this recipe during my first spring in a new home with a thriving rhubarb patch. After experimenting with countless rhubarb desserts, these bars quickly became the neighborhood favorite at our annual garden party.
Ingredients
- For the crust:
- All purpose flour: creates the perfect tender yet sturdy foundation
- Cold butter: must be cold to achieve that perfect crumbly texture
- Powdered sugar: gives the crust a melt in your mouth quality without graininess
- For the filling:
- Granulated sugar: balances the natural tartness of rhubarb perfectly
- All purpose flour: acts as a thickener for the custard
- Salt: enhances all the flavors and balances sweetness
- Large eggs: provide structure and richness to the custard layer
- Diced rhubarb: look for firm stalks with vibrant color for best results
- For the topping:
- Powdered sugar: adds a beautiful finishing touch and extra sweetness
Step-by-Step Instructions
- Prepare the crust:
- Combine flour and powdered sugar in a medium bowl. Cut in cold butter using a pastry blender or two knives until the mixture looks like coarse crumbs. The butter pieces should be no larger than peas for the perfect texture.
- Create the base:
- Press the crumb mixture firmly and evenly into a greased 9×13 inch baking dish. Use the bottom of a measuring cup to ensure an even layer with no gaps or thin spots.
- Prebake the crust:
- Bake at 350°F for exactly 10 minutes until just barely set but not browned. This partial baking ensures the crust wont get soggy when the filling is added.
- Prepare the filling:
- While the crust bakes, whisk together granulated sugar, flour, and salt in a large bowl. Add eggs and whisk vigorously until completely smooth and slightly thickened.
- Add the star ingredient:
- Gently fold in the diced rhubarb, making sure pieces are evenly distributed throughout the custard mixture.
- Assemble and bake:
- Pour the rhubarb custard mixture over the warm prebaked crust, spreading to ensure even distribution. Return to the oven and bake for 35 to 40 minutes until the custard is set with just a slight jiggle in the center.
- Cool completely:
- Allow the bars to cool fully at room temperature before cutting to ensure clean slices and proper setting of the custard.
- Finish and serve:
- Dust with powdered sugar just before serving for a beautiful presentation.
I particularly love using garden fresh rhubarb for this recipe. My grandmother taught me to harvest rhubarb stalks by gently pulling them from the base rather than cutting them, which encourages more growth throughout the season. This small detail connects me to generations of family bakers every time I make these bars.
Rhubarb Selection Tips
When shopping for rhubarb, look for firm, crisp stalks with shiny skin. The color can range from pale green to deep red, but color doesnt necessarily indicate ripeness or flavor. Avoid stalks that are limp or have brown spots. If you find rhubarb with leaves attached, be sure to remove and discard them as they contain toxic compounds. Fresh rhubarb can be stored in the refrigerator wrapped in a damp paper towel inside a plastic bag for up to a week.
Make Ahead Options
These bars are perfect for preparing in advance. You can make the entire recipe up to two days before serving and store covered in the refrigerator. For the freshest presentation, wait to dust with powdered sugar until just before serving. You can also freeze the baked and cooled bars for up to three months. Simply wrap individual portions in plastic wrap and place in an airtight container. Thaw overnight in the refrigerator for the best texture.
Serving Suggestions
While these bars are delicious on their own, they become truly spectacular when paired with complementary flavors. Try serving with a dollop of freshly whipped cream or a small scoop of vanilla bean ice cream. For a more sophisticated dessert, add a drizzle of warm honey or a sprinkle of crushed pistachios. These bars pair beautifully with afternoon tea or as the finale to a spring dinner party.
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Recipe FAQs
- → Can I use frozen rhubarb instead of fresh?
Yes, frozen rhubarb works well in this dessert. Thaw completely and drain excess liquid before measuring and adding to the custard mixture. Pat dry with paper towels to prevent the filling from becoming too wet.
- → How do I know when the custard filling is properly set?
The custard is set when the center is no longer jiggly and the edges have turned slightly golden. A toothpick inserted into the center should come out mostly clean, perhaps with a few moist crumbs but no wet batter.
- → How should I store these bars?
Store the bars in an airtight container in the refrigerator for up to 4 days. The custard contains eggs, so refrigeration is necessary for food safety. Allow them to come to room temperature before serving for the best flavor, or enjoy them chilled.
- → Can I substitute strawberries or other fruits for the rhubarb?
While rhubarb provides the signature tartness, you can experiment with strawberries (the classic rhubarb companion), raspberries, or blackberries. Firmer fruits work best as they hold their shape during baking. Adjust sugar amounts based on the sweetness of your chosen fruit.
- → Why did my shortbread crust turn out too crumbly?
A too-crumbly crust usually means the butter wasn't incorporated well enough or the crust wasn't pressed firmly into the pan. Make sure to cut the butter in until you achieve a coarse crumb texture, then press firmly and evenly into the baking dish before pre-baking.
- → Can I make these bars ahead of time for a party?
Absolutely! These bars actually benefit from chilling overnight, which allows the flavors to meld and makes them easier to cut cleanly. Prepare them a day ahead, refrigerate, and dust with powdered sugar just before serving for the freshest presentation.