Nothing says nostalgic bakery comfort food quite like a Classic Vanilla Slice (affectionately known to many as a “snot block” or Mille-Feuille). This iconic treat features thick, velvety vanilla custard sandwiched between layers of perfectly crisp, flaky puff pastry, finished with a generous dusting of powdered sugar.
If you’ve been looking for a foolproof way to recreate this bakery favorite at home with maximum flavor and minimal fuss, this is the recipe for you.

Why This Recipe Works
- The Double-Vanilla Punch: Using both custard powder and real vanilla bean paste creates a deep, aromatic flavor and that classic golden hue.
- Foolproof Thick Custard: The combination of egg yolks, cornstarch-based custard powder, and butter ensures a sliceable custard that holds its shape beautifully without spilling out when you take a bite.
- Effortless Crisp Layers: Using high-quality pre-made puff pastry sheets gives you those sky-high, buttery layers without hours of laminating dough.
Ingredients You’ll Need
- Puff Pastry Sheets: 2 sheets (frozen, thawed)
- Vanilla Custard Powder: ½ cup
- Whole Milk: 2 cups
- Granulated Sugar: ⅔ cup (divided into two ⅓ cup portions)
- Unsalted Butter: 50g (cubed, at room temperature)
- Egg Yolks: 4 large eggs
- Vanilla Bean Paste: 1 tbsp
- Powdered Sugar: For dusting
Step-by-Step Instructions
1. Bake the Puff Pastry
- Preheat & Prep: Preheat your oven to 400°F (200°C). Line two large baking sheets with parchment paper.
- Dock the Pastry: Place your thawed puff pastry sheets onto the trays. Prick them all over with a fork (this prevents them from puffing up too unevenly).
- Bake Until Golden: Place another sheet of parchment paper on top of each pastry sheet, followed by a second baking tray to weight them down slightly. Bake for 15–20 minutes until deeply golden brown and crisp. Remove from the oven and let cool completely.
- Trim: Trim both sheets to perfectly fit an 8×8 inch (20×20 cm) square baking pan. Place one pastry sheet at the bottom of the lined pan.
2. Make the Rich Vanilla Custard
- Slurry: In a medium bowl, whisk together the custard powder, 4 egg yolks, and about ½ cup of the cold milk until smooth and lump-free.
- Heat the Base: In a medium saucepan over medium heat, combine the remaining milk, both portions of sugar (⅔ cup total), and the vanilla bean paste. Bring just to a simmer, stirring to dissolve the sugar.
- Temper & Thicken: Slowly pour a steady stream of the hot milk mixture into your egg yolk/custard slurry, whisking constantly to prevent the eggs from scrambling. Pour the entire mixture back into the saucepan.
- Cook until Thick: Whisk vigorously over medium-low heat for 3–5 minutes as it comes to a boil. It will thicken up significantly. Once thick and glossy, remove from heat and immediately whisk in the 50g of butter until completely smooth and melted.
3. Assemble and Chill
- Pour: Immediately pour the hot vanilla custard over the bottom pastry layer in your lined baking pan. Smooth the top evenly with a spatula.
- Top: Place the second baked pastry sheet gently on top of the hot custard, pressing down very lightly so it adheres.
- Chill: Allow the slice to cool to room temperature, then transfer it to the refrigerator for at least 4 hours (preferably overnight) to set completely firm.
4. Slice and Serve
- Dust: Lift the set vanilla slice out of the pan using the parchment paper handles. Dust the top sheet generously with powdered sugar.
- The Clean Cut: Use a sharp, serrated bread knife. Wipe the blade clean with a hot, damp cloth between every single cut to ensure beautiful, clean bakery-style edges.
Pro-Tips for the Perfect Slice
Preventing Soggy Pastry: Ensure your pastry sheets are baked until they are a deep golden brown, not pale. A well-baked pastry resists absorbing moisture from the custard, staying crispy for longer.
Getting Clean Cuts: If you struggle to cut through the top layer of pastry without squishing the custard, you can pre-cut the top pastry sheet into squares before placing it on top of the hot custard. When it comes time to serve, just cut straight down through the lines!







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