Rhubarb & Custard Blondies are a chewy, bittersweet baked treat where tender rhubarb and velvety custard layers meet rich chocolate and custard-infused dough. Ideal for breakfast, desserts, or afternoon snacks. Enjoy a balanced flavor profile that’s both nostalgic and modern.
| Prep Time | Cook Time | Total Time | Servings | Difficulty | Cuisine |
|---|---|---|---|---|---|
| 20 minutes | 45 minutes | 1 hour 5 minutes | 12-16 squares | Moderate | British-Inspired Desserts |
Why This Recipe Works
Rhubarb & Custard Blondies thrive on contrast: the tart rhubarb and creamy custard cut through the blondie’s fudgy sweetness. The custard powder in the base adds a subtle vanilla depth that harmonizes with white chocolate. Baking it turns custard topping into a jammy texture, creating a cake-like interior with contrasting layers. One bite offers both tangy brightness and gooey richness.
This recipe prioritizes simplicity. Authentic ingredients like fresh rhubarb and custard powder ensure no artificial additives. Scaling portions for batches is seamless, making these perfect for family gatherings or packed lunchboxes. Unlike traditional blondies, the custard element introduces a nostalgic twist ideal for vintage-inspired desserts.
Ingredients
| Ingredient | Quantity | Notes |
|---|---|---|
| Butter | 225 g plus extra for tin | Melted with sugar for base; cold butter creates texture |
| Light Brown Sugar | 200 g | For deep sweetness; substitute 50g with coconut sugar for lower GI |
| Caster Sugar | 100 g | Used in rhubarb stew and custard topping |
| Plain Flour | 150 g | Sieve for lighter texture; gluten-free option available |
| Custard Powder | 50 g | Forms custard-enriched dough; skip for basic blondies |
| Baking Powder | ½ teaspoon | Optional for fluffier top layer |
| Vanilla Extract | 2 teaspoon | Amplifies custard flavor; substitute with custard sauce |
| Rhubarb | 200 g | Chopped into 3-4 cm pieces; frozen rhubarb works for topping |
| White Chocolate | 250 g (chips or chopped) | Use 100g semi-sweet chocolate for bittersweet alternative |
Step-by-Step Instructions
-
Prepare Rhubarb Topping
In a wide pan, combine rhubarb, 75g caster sugar, and 2 tbsp water. Cookuntil jammy, about 10 minutes. Cool completely. If using custard powder, mix 50g with 2 tbsp cold milk, cook to desired thickness, and set aside.
-
Melt and Cool Sugar-Butter Mixture
Heat butter and both sugars in a pan over low heat. Stir until glossy. Remove from heat, let cool 10 minutes.
-
Combine Dry Ingredients
Sift flour, custard powder, and baking powder into a bowl. Butter and line a 9×13 inch tin with parchment.
-
Blend Wet and Dry Ingredients
Whisk eggs into cooled sugar-butter mixture. Fold in 250g white chocolate and vanilla. Pour batter into tin.
-
Create Marbled Topping
Drop spoonfuls of rhubarb mixture and custard over batter. Swirl with a skewer to form marbled patterns.
-
Bake and Cool
Bake at 180°C (fan 160°C) for 40-50 minutes until edges are set. Cool completely before slicing.
Chef Tips for Perfect Results
- Brown Sugar Foams Better – The moisture in light brown sugar creates air bubbles for a chewy texture.
- Don’t Rush Cooling – Letting blondies cool entirely before slicing ensures clean cuts and prevents crumbling.
- Swirl Technique – Use a toothpick in a zig-zag pattern for better marbling. Avoid over-mixing topping layers.
- Butter Control – Using ½ tbsp cold butter for the tin prevents sticking without excess oil seepage into batter.
Common Mistakes to Avoid
- Undercooked Center – Check doneness by inserting a skewer; center should be slightly soft but not wet.
- Overbaking Crust – Check every 5 minutes from 35 minutes; cover with foil if browning too quickly.
- Wet Topping – Ensure rhubarb is fully cooked and cooled before adding to hot batter. Cold-to-hot contact causes sogginess.
- Using Milk Chocolate – Milk chocolate’s acidity clashes with rhubarb.Stick to white chocolate for neutral base.
Variations and Substitutions
| Ingredient | Substitution | Impact on Flavor |
|---|---|---|
| White Chocolate | Dark Chocolate (70%+ cacao) | Adds bittersweet contrast to rhubarb’s tartness |
| Custard Powder | Orange Zest + Extra Butter | Creates citrus aroma similar to custard |
| Rhubarb | Strawberries (with 1 tsp balsamic vinegar) | Softens into a jammy texture without tartness |
| Butter | Olive Oil (125g) | Provides moist texture but reduces richness |
Serving Suggestions and Pairings
Serve Rhubarb & Custard Blondies with: iced herbal teas like Earl Grey for rhubarb balance; strong coffee to cut sweetness; for casual meals, pair with yogurt or whipped cream for decadent contrast. These also work as mini bites for harvest festivals, baby showers, or afternoon tea spreads.
Storage and Reheating
| Method | Duration | Instructions |
|---|---|---|
| Room Temperature | 3 days | Store in an airtight container |
| Refrigerated | 1 week | Place in parchment-lined container |
| Frozen | 3 months | Wrap tightly in foil; thaw at room temperature |
| Reheating | 2 minutes | Use microwave at 60% power or oven at 160°C |
Nutritional Information
| Nutrient | Amount per Serving |
|---|---|
| Approximate calories | 220 kcal |
| Protein | 2 g |
| Fat | 13 g |
| Carbohydrates | 25 g |
| Fiber | 0.5 g |
| Sugar | 17 g |
| Sodium | 40 mg |
Frequently Asked Questions
Can I use rhubarb canned in syrup?
No canned varieties recommended. The syrup adds excess sugar; undercooked canned rhubarb creates overly wet texture.
How to tell if rhubarb is done baking?
Insert a knife; it should come out clean but without liquid. Edges will recede from pan walls.
Why is my custard layer running?
Rhubarb wasn’t cooked long enough. Boil until jammy and excess moisture evaporates before topping dough.
Can this be made vegan?
Use salted butter substitute and plant-based white chocolate. Replace eggs with 1/3 cup applesauce plus 1 tbsp ground flax.
Best occasion to serve this recipe?
Perfect for autumn-themed gatherings or British-inspired tea parties. Winter-friendly with cinnamon-sugar toppings.
Conclusion
Rhubarb & Custard Blondies deliver a masterful fusion of sweet and tart textures. The custard-infused dough provides a moist base while rhubarb’s tang prevents overwhelming sweetness. Whether sliced for afternoon snacking or decadently cut for formal events, these blondies impress with both flavor complexity and nostalgic simplicity. For best results, let them chill in the fridge for firmer texture before serving.
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Rhubarb & Custard Blondies
- Total Time: 65
- Yield: 12-16 squares 1x
- Diet: Vegetarian
Description
Chewy, bittersweet blondies with tender rhubarb, velvety custard layers, and rich chocolate. Perfect for breakfast or desserts, combining tart rhubarb, creamy custard, and fudgy dough for a nostalgic, modern treat.
Ingredients
225 g butter (plus extra for greasing tin)
200 g light brown sugar
100 g caster sugar
150 g plain flour (gluten-free option available)
50 g custard powder
½ teaspoon baking powder
2 teaspoons vanilla extract
200 g rhubarb (chopped 3–4 cm pieces)
250 g white chocolate (chips or chopped)
40 ml water (for custard topping)
Instructions
Preheat oven to 350°F (175°C). Grease a 9×9 inch tin.
Melt 225 g butter, mix with 200 g light brown sugar for 5 minutes until golden.
Stir in 150 g flour, 50 g custard powder, ½ teaspoon baking powder, and 2 teaspoons vanilla.
Spread half the mixture into the tin. Top with 200 g stewed rhubarb (simmer 200 g rhubarb with 100 g caster sugar for 5 minutes).
Drizzle with 40 ml warm water and remaining 50 g caster sugar mixed with 50 g custard powder.
Sprinkle with 250 g white chocolate pieces. Bake 45 minutes until golden.
Cool completely before cutting into 12-16 squares.
Notes
Freeze rhubarb for a contrasting texture. Skip custard powder for basic blondies. Store in an airtight container for 3 days.
- Prep Time: 20
- Cook Time: 45
- Category: Desserts
- Method: Baking
- Cuisine: British-Inspired Desserts
Nutrition
- Serving Size: 1 square
- Calories: 300
- Sugar: 32g
- Sodium: 180mg
- Fat: 14g
- Saturated Fat: 8g
- Carbohydrates: 42g
- Fiber: 1g
- Protein: 3g
- Cholesterol: 20mg
