Rhubarb Custard Bars

The aroma of freshly baked rhubarb custard bars wafts through the kitchen, creating an inviting warmth that draws everyone in. With a buttery shortbread base, creamy custard filling, and tart rhubarb topping, these bars combine flavors and textures beautifully. In just about an hour, you can create a delightful dessert that’s both comforting and refreshing.

This recipe is perfect for anyone looking to impress at gatherings or treat their family to a special dessert. Whether it’s a picnic, potluck, or a simple afternoon tea, these bars shine in any setting. Best of all, they can be prepared ahead of time and stored in the refrigerator.

Why You’ll Love This Recipe

• The buttery shortbread base adds a rich flavor and crumbly texture.
• The creamy custard filling strikes a perfect balance between sweetness and tartness.
• The vibrant rhubarb slices provide a delightful burst of flavor in every bite.
• It’s simple to make, with straightforward steps and minimal equipment.

What You’ll Need

Here’s what you’ll need to make delicious rhubarb custard bars.

For the Base

• 250g All-Purpose Flour (2 cups)
• 100g Sugar (1/2 cup)
• 200g Cold Unsalted Butter (3/4 cup + 2 tbsp)
• 1/2 tsp Baking Powder
• Pinch of Salt

For the Custard

• 4 Large Egg Yolks
• 200g Sugar (1 cup)
• 3 tbsp Cornstarch
• 240ml Whole Milk (1 cup)
• 120ml Heavy Cream (1/2 cup)
• 1 tsp Vanilla Extract

For the Topping

• 300–350g Rhubarb, thinly sliced (2 1/2–3 cups)
• 1 tbsp Sugar

Use fresh rhubarb for best flavor.

Substitutions & Swaps

• Unsalted butter can be replaced with margarine.
• Whole milk can be substituted with almond milk for a dairy-free option.
• For a sweeter custard, increase sugar to taste.
• Cornstarch can be replaced with arrowroot powder for thickening.

How to Make It

Here’s how to prepare these delicious rhubarb custard bars.

1. Preheat and prepare

Preheat the oven to 175°C (350°F). Line a 23cm (9-inch) square pan with parchment paper for easy removal.

2. Make the base

Combine dry ingredients. In a large bowl, combine the flour, sugar, baking powder, and salt. Add the cold butter and rub it in with your fingertips (or pulse in a food processor) until crumbly.

3. Form the crust

Press into the pan. Press 2/3 of the mixture firmly into the base of your prepared pan. Bake for 12–15 minutes, until lightly golden. Set the remaining 1/3 aside for the crumble.

4. Whisk the custard

Prepare custard mixture. In a medium bowl, whisk together the egg yolks, sugar, and cornstarch until smooth. Gradually whisk in the milk, cream, and vanilla extract until fully combined and lump-free.

5. Assemble

Layer the custard. Pour the uncooked custard mixture over the pre-baked shortbread base. Scatter the sliced rhubarb evenly across the top of the custard and gently press to embed.

6. Add the crumble

Top with remaining mixture. Sprinkle the reserved shortbread mixture over the top as a crumble.

7. Bake

Cook thoroughly. Bake for 35–40 minutes, until the top is golden and the custard is mostly set with just a slight jiggle in the center.

8. Cool and chill

Let cool completely. Cool completely, then refrigerate for at least 2 hours (or overnight) before slicing. Dust with icing sugar just before serving.

How to Store It

Fridge: Store for up to 5 days in an airtight container.
Freezer: Yes, can be frozen for up to 3 months.
Reheat: Microwave for 15-20 seconds on low.

Tips for Best Results

• Ensure your butter is cold for a flaky base.
• Use fresh, seasonal rhubarb for optimal flavor.
• Don’t skip the chilling time to set the custard properly.
• Dust with icing sugar just before serving for a beautiful finish.

Serving Suggestions

• Pair these bars with a dollop of whipped cream.
• Serve with a scoop of vanilla ice cream for a decadent treat.
• Great for spring or summer gatherings, adding a refreshing touch.