Shortbread Custard Bars with Rhubarb and Citrus
These bars have a buttery shortbread base flavored with orange zest, a tangy rhubarb and citrus custard filling, and a layer of rich pastry cream on top.
- 250 g (2 cups) all-purpose flour
- 2 sticks unsalted butter chilled and cut into pieces
- ½ cup granulated sugar
- ½ tsp salt
- 2 tsp fresh orange zest
- 1 ¼ lbs fresh rhubarb cut into small pieces
- ¾ cup granulated sugar divided
- ¼ cup water
- 1 tbsp lemon juice
- 1 ½ tsp fresh orange zest
- 6 large egg yolks
- 5 tbsp unsalted butter
- 2 cups milk whole or 2%
- ¼ cup + ⅓ cup granulated sugar divided
- 1 whole egg
- 2 egg yolks
- ¼ cup cornstarch
- 2 tbsp unsalted butter
- A dash of vanilla extract about ½ - 1 tsp
- Powdered sugar for dusting
- Zest of 1 lemon
Preheat the oven to 325º F and wash your hands.
Add the shortbread ingredients to a bowl and use your fingers to work the cold butter into the dry ingredients until the mixture is crumbly and well-combined. Don't overwork.
Press the dough firmly and evenly into a baking pan. Prick all over with a fork.
Bake for 35 minutes or until light golden brown, then remove from the oven and turn the heat up to 350º F. Meanwhile, prepare the custard.
Add the rhubarb, ¼ cup of the sugar, and the water to a saucepan over high heat. Bring to a boil, then lower the heat to medium-low and simmer uncovered, stirring often, until the rhubarb is very soft and mushy, about 10 minutes.
Transfer the rhubarb mixture to a blender or food processor, add the orange zest, and process until smooth. Add to a small saucepan along with the rest of the sugar, egg yolks, and lemon juice. Whisk over medium heat until thoroughly combined.
Add the butter and whisk constantly until it's fully melted and incorporated. Remove from heat and pour over the baked shortbread. Return to the oven (now at 350º) and bake for 15 minutes or until the custard is set.
Cool in the pan to room temperature, then put in the fridge to cool completely.
Stir together the milk and ¼ cup of the sugar in a large saucepan. Bring to a simmer over medium heat. Meanwhile, in a separate heatproof bowl, whisk together the egg, egg yolks, cornstarch, and the rest of the sugar.
When the milk mixture is simmering but *not* rapidly boiling, remove from heat and pour half into the egg mixture, whisking constantly so the eggs don't scramble. Pour this mixture back into the rest of the milk and whisk constantly over medium heat until it thickens.
Remove from the heat and stir in the butter and vanilla until the butter is melted. Transfer the pastry cream to a cold bowl and let sit at room temperature until the cream is no longer warm to the touch.
Spread the cream evenly over the chilled shortbread bars. Freeze for one hour to harden.
Top with a sprinkle of powdered sugar and the zest of one lemon. Use a sharp knife to cut into individual bars.