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Rhubarb Custard Crumble Bars

By Beginnerbakes Editorial TeamPublished Jun 28, 2026 | Updated Oct 6, 2026
American Under review Beginner BakingRhubarbCustard BarsCrumble Bars

Rhubarb Custard Crumble Bars layer buttery crust, vanilla custard, tart rhubarb, and golden oat crumble for an approachable seasonal bake.

Rhubarb Custard Crumble Bars
Prep Under review
Cook Under review
Total Under review
Servings 16
Difficulty easy
Cuisine American

Recipe Details

PrepUnder review
CookUnder review
TotalUnder review
Servings16
Difficultyeasy
CuisineAmerican
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Ingredients

Servings 16
  • 1 1/2 cups all-purpose flour
  • 1 cup rolled oats
  • 3/4 cup sugar, divided
  • 1/2 teaspoon cinnamon
  • 1/2 teaspoon kosher salt
  • 3/4 cup cold butter, cubed
  • 2 cups chopped rhubarb
  • 2 large eggs
  • 1/2 cup milk
  • 1 teaspoon vanilla extract
  • 1 tablespoon cornstarch
Ingredients for Rhubarb Custard Crumble Bars
Ingredients for Rhubarb Custard Crumble Bars

Instructions

  1. Preheat the oven to 350 degrees F. Line a 9-inch square pan with parchment.
  2. Mix flour, oats, 1/2 cup sugar, cinnamon, and salt. Cut in cold butter until crumbly.
  3. Press two-thirds of the mixture into the pan and bake for 12 minutes.
  4. Whisk eggs, milk, vanilla, cornstarch, and remaining sugar until smooth.
  5. Scatter rhubarb over the crust, pour custard over it, and sprinkle with remaining crumble.
  6. Bake for 28 to 30 minutes, until the center is set and the crumble is golden. Cool before slicing.
Rhubarb Custard Crumble Bars process image
Rhubarb Custard Crumble Bars process image

Tips

Equipment Needed

Use a 9-inch square pan, parchment, a pastry cutter or fork, and a medium mixing bowl. Parchment overhang makes the cooled bars much easier to lift and slice.

Ingredient Prep Notes

Keep the butter cold so the crust and crumble bake up tender instead of greasy. Chop rhubarb into small even pieces so it softens before the custard sets.

Oven Note

Bake on the center rack and cool the bars fully before cutting. If the crumble browns early, tent the pan loosely with foil for the final minutes.

Easy Upgrade Ideas

Add orange zest to the custard or sliced strawberries with the rhubarb. A light dusting of powdered sugar makes the bars look bakery-ready.

Timing note

Cooling before slicing is additional to baking. Allow additional time as needed; no tested total is claimed.

Storage and Reheating

Refrigerate bars in an airtight container for up to 4 days. Serve chilled or let stand at room temperature for 15 minutes.

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