These rhubarb custard bars are soft, buttery, and perfectly tart. They’re like a pie and a lemon bar had a spring baby. I love them fresh from the fridge on a warm day.
Make them ahead, bring to a picnic, or just eat one over the sink. No shame.
What You’ll Need
For the Crust:
- 1 cup (2 sticks) unsalted butter, cold and cubed
- 2 cups all-purpose flour
- ½ cup powdered sugar
- ¼ teaspoon salt
For the Custard Filling:
- 4 large eggs
- 1¾ cups granulated sugar
- ½ cup all-purpose flour
- ½ teaspoon salt
- ¾ cup heavy cream
- 1 teaspoon vanilla extract
- 3 cups rhubarb, diced (fresh or thawed if frozen)
Why I Love This Recipe
This recipe came from a little church cookbook my grandma used to keep in her kitchen drawer. Every spring, when rhubarb popped up in the backyard, we’d make this together. Simple, sweet, and tart – it tastes like sunshine.
- Buttery crust that melts in your mouth
- Creamy custard with just the right tang
- Great for potlucks, spring brunches, or straight from the fridge
- Uses basic pantry staples + fresh rhubarb
Makes: 12 bars
Total Time: About 1 hour
Prep: 15 minutes
Bake: 45 minutes
Why This Recipe Works (Quick Science)
The cold butter in the crust creates flaky layers as it bakes – kind of like a shortbread.
The eggs and cream create a custard that sets gently around the tart rhubarb.
Flour in the filling keeps the custard sturdy, so you get neat bars that slice clean.
Pro Tips
- Dice rhubarb evenly so it cooks at the same rate.
- Chill the bars before slicing – they cut better when cold.
- Use parchment paper to lift bars out cleanly.
- You can prep the crust ahead and freeze it unbaked.
- Don’t skip the salt – it balances the sweet.
Tools You’ll Need
- 9×13″ baking dish
- Mixing bowls
- Measuring cups and spoons
- Whisk
- Knife and cutting board
- Parchment paper
Substitutions & Variations
- Use half rhubarb, half strawberries for a sweeter twist
- Sub almond extract for vanilla for a nutty flavor
- Dairy-free? Use coconut cream in place of heavy cream
- Gluten-free? Use a GF flour blend for both crust and filling
Make-Ahead Tips
- Bake the night before and chill overnight
- Crust can be prepped and frozen for up to 2 weeks
- Bars freeze well – slice and wrap individually
Instructions
Step 1: Make the Crust
In a bowl, mix 2 cups all-purpose flour, ½ cup powdered sugar, and ¼ teaspoon salt.
Add 1 cup (2 sticks) cold, cubed unsalted butter. Use your fingers or a pastry cutter to blend until the mixture is crumbly.
Step 2: Press and Bake the Crust
Press the crust mixture evenly into a parchment-lined 9×13″ pan. Bake at 350°F (175°C) for 15 minutes, or until lightly golden.
Step 3: Mix the Custard
While the crust bakes, whisk together 4 large eggs, 1¾ cups granulated sugar, ½ cup all-purpose flour, and ½ teaspoon salt in a large bowl until smooth.
Step 4: Add Cream, Vanilla & Rhubarb
Whisk in ¾ cup heavy cream and 1 teaspoon vanilla extract. Fold in 3 cups diced rhubarb (fresh or thawed if frozen) gently.
Step 5: Pour and Bake
Pour the custard mixture over the baked crust. Return to the oven and bake at 350°F for 40–45 minutes, or until the custard is set and lightly golden on top.
Step 6: Cool and Slice
Let the bars cool fully at room temperature, then refrigerate for 1–2 hours.
Slice into squares and dust with powdered sugar if desired.
Leftovers & Storage
- Store in the fridge, tightly covered, for up to 5 days
- Freeze individually wrapped bars up to 2 months
- Best served chilled straight from the fridge
Common Mistakes
- Not chilling before slicing – they’ll fall apart
- Overbaking – custard should still have a slight jiggle in the center
- Using warm rhubarb – always use cold or room-temp so custard sets right
- Not lining the pan – parchment helps lift bars out clean
What to Serve With
- A hot cup of coffee or tea
- A scoop of vanilla ice cream
- A dollop of whipped cream
- As part of a spring brunch spread
FAQ
Can I use frozen rhubarb?
Yes! Thaw and drain well before using.
Can I make these dairy-free?
Try canned coconut cream instead of heavy cream. The flavor will change a little but still be delicious.
Why is my custard runny?
It likely wasn’t baked long enough or cooled fully before slicing.
Can I reduce the sugar?
You can cut the sugar in the filling by about ¼ cup, but it will be more tart.
Let’s Bake It!
I hope these bars bring a little sunshine into your kitchen like they do in mine.
If you try them, leave a comment and let me know how it went – or ask a question if you get stuck!
