Rhubarb Crumble and Custard

Rhubarb Crumble and Custard


  • 1 1/2 pounds frozen, chopped rhubarb
  • 3/4 cup granulated sugar
  • 1 tablespoon all-purpose flour
  • 1 teaspoon lemon zest
  • 1 teaspoon baking soda
  • 1 teaspoon cinnamon


  • 1 cup all-purpose flour
  • 1 cup dark brown sugar
  • 1/2 cup oats
  • 1/2 teaspoon cinnamon
  • 1/2 teaspoon salt
  • 4 tablespoons cold, unsalted butter


  • 1/4 cup granulated sugar
  • pinch salt
  • 1 tablespoon cornstarch
  • 1 1/4 cups whole milk
  • 1/4 cup cream
  • 3 egg yolks
  • 2 teaspoons vanilla
  • 2 tablespoons cold, unsalted butter

Baker's Note:  I made a few modifications (improvements, in my opinion) to the author's recipe, but one ingredient I found interesting and unusual, and did not change.  The author notes that the baking soda in the rhubarb filling helps to neutralize the acidity of the rhubarb, making it less tart and more palatable, perhaps so that you can get by with less sugar than if no baking soda were added.  This is something I need to research further.

Preheat the oven to 350 and spray a deep dish pie pan or 8x8 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.

Use a pastry cutter to combine all the topping ingredients in a large bowl until moist and crumbly.  Stir up the rhubarb filling, sprinkle the crumble topping over the fruit, and bake for 45-50 minutes, until the topping is golden brown and the filling is bubbling.

Meanwhile, make the custard.  In a saucepan whisk together the sugar, salt and cornstarch.  Gradually whisk in the milk and cream, then the egg yolks.  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 vanilla and butter.  The custard can be served warm, but I prefer it chilled.  The cool, creamy custard spooned over the hot crumble is lovely.

Recipe adapted from The Unofficial Harry Potter Cookbook by Dinah Bucholz