# Ingredient List:
→ Rhubarb Layer
01 - 14 oz fresh rhubarb, trimmed and chopped
02 - 5.3 oz granulated sugar
03 - 1 tablespoon fresh lemon juice
04 - 1 tablespoon cornstarch
→ Shortbread Base & Crumble
05 - 8.8 oz all-purpose flour
06 - 3.5 oz rolled oats
07 - 5.3 oz unsalted butter, cold and cubed
08 - 3.5 oz light brown sugar
09 - 0.5 teaspoon salt
→ Custard Layer
10 - 10 fl oz whole milk
11 - 2 large egg yolks
12 - 2.1 oz granulated sugar
13 - 2 tablespoons cornstarch
14 - 1 teaspoon vanilla extract
# Directions:
01 - Preheat oven to 350°F. Line a 9-inch square baking pan with parchment paper, allowing overhang on the sides for easy removal.
02 - In a saucepan, combine chopped rhubarb, 5.3 oz sugar, lemon juice, and 1 tablespoon cornstarch. Cook over medium heat, stirring frequently, until rhubarb softens and the mixture thickens, approximately 8-10 minutes. Transfer to a bowl and allow to cool.
03 - In a large mixing bowl, combine flour, rolled oats, light brown sugar, and salt. Using your fingertips or a pastry cutter, work in the cold cubed butter until the mixture resembles coarse breadcrumbs.
04 - Press two-thirds of the crumble mixture firmly into the bottom of the prepared pan, creating an even, compact base. Reserve the remaining crumble for topping.
05 - Bake the base layer for 15 minutes until lightly golden. Remove from oven and allow to cool slightly.
06 - Heat the milk in a saucepan until steaming but not boiling. In a separate bowl, whisk together egg yolks, 2.1 oz sugar, and 2 tablespoons cornstarch until smooth. Slowly pour the hot milk into the egg mixture while whisking constantly. Return the combined mixture to the saucepan and cook over medium heat, stirring continuously, until thickened, approximately 2-3 minutes. Remove from heat and stir in vanilla extract.
07 - Spread the cooled rhubarb filling evenly over the baked base layer. Pour the prepared custard sauce carefully over the rhubarb.
08 - Sprinkle the reserved crumble mixture evenly over the custard layer, distributing it to cover the surface completely.
09 - Bake for 30 minutes, or until the crumble topping is golden brown and the custard layer is just set.
10 - Allow the bars to cool completely in the pan at room temperature. Transfer to the refrigerator and chill for at least 2 hours before lifting out of the pan and cutting into 16 individual bars.
