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A bowl of rhubarb crumble, served with vanilla bean custard.

Rhubarb Crumble and Custard

Heather Smoke
Sweet and tart rhubarb crumble with cinnamon oat streusel, served with creamy vanilla bean custard.

All recipes on Curly Girl Kitchen are developed for high altitude at 5,280 feet.

5 from 1 vote
Prep Time 20 mins
Cook Time 1 hr
Total Time 1 hr 20 mins
Course Dessert
Cuisine American


Vanilla Bean Custard

  • ¼ cup granulated sugar
  • tsp coarse Kosher salt (if using table salt, use half the amount)
  • 2 tbsp corn starch
  • 1 ¼ cups whole milk
  • ¼ cup heavy whipping cream
  • 3 egg yolks
  • ½ vanilla bean, seeds scraped
  • 2 tbsp unsalted butter

Rhubarb Filling

  • 1 ½ lbs fresh rhubarb (or frozen and thawed), diced in 1/2 inch pieces
  • ½ cup granulated sugar
  • 1 tbsp all-purpose flour
  • 1 tsp fresh lemon zest
  • ¼ tsp baking soda
  • ¼ tsp ground cinnamon

Crumb Topping

  • 1 cup all-purpose flour, spooned and leveled
  • ¾ cup dark brown sugar, lightly packed
  • ½ cup old-fashioned oats
  • ½ tsp ground cinnamon
  • ½ tsp coarse Kosher salt (if using table salt, use half the amount)
  • 4 tbsp unsalted butter, melted



  • In a saucepan whisk together the sugar, salt and cornstarch.  Gradually whisk in the milk and cream, then the egg yolks and scraped vanilla bean seeds.
  • Over medium heat, cook the custard, while whisking constantly, until thickened enough to coat the back of a spoon.  Remove from the heat and whisk in the butter.
  • The custard can be served warm, but I prefer it chilled.  The cool, creamy custard spooned over the hot crumble is lovely.
  • Pour the custard into a lidded container and refrigerate until needed. Stir the custard until smooth before serving with the rhubarb crumble.


  • Preheat the oven to 350 and spray a deep dish pie pan or a 9 or 10-inch baking dish with non-stick spray.
  • Toss all the filling ingredients together and spread into the pan.  Bake for 10 minutes while you make the crumble topping.


  • In a bowl (I just use the same one I mixed the filling in), combine the flour, brown sugar, oats, cinnamon and salt. Drizzle with the melted butter and stir until moistened and crumbly.
  • Remove the pan from the oven, and stir up the filling. Sprinkle the topping over the rhubarb.
  • Return the pan to the oven, and bake for 40-45 minutes, until the filling is bubbling and the topping is golden brown.


  • Cool the rhubarb crumble for about 30 minutes.
  • Serve scoops of the warm crumble, with cool and creamy custard on the side.


  • Rhubarb crumble is best served warm, the day it's made, but it still tastes good the next day, even cold.  Leftovers should be covered and refrigerated, and eaten within 2 days.
  • Refrigerate the leftover custard and eat within 1 week.
  • Recipe is adapted from The Unofficial Harry Potter Cookbook.
Keyword Crumbles and Crisps, Custard, Rhubarb, Vanilla Bean
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