This Creamy Vanilla Slice with Flaky Puff Pastry layers thick vanilla bean custard between two crisp sheets of golden pastry. A dusting of powdered sugar finishes each square, letting the buttery pastry and vanilla filling stand out.
How to Get Crisp, Flat Puff Pastry
Roll each thawed pastry sheet into a roughly 9-inch square and prick it all over with a fork. Cover each sheet with parchment and set a second baking tray on top. The weight keeps the pastry flat enough to stack and slice.
Bake until the sheets are evenly golden and crisp, then cool them completely before trimming. Use a serrated knife and a gentle sawing motion to cut each sheet to fit the inside of an 8-inch square pan. A paper template cut to the size of the pan’s interior makes it easier to trim both sheets evenly.
How to Make Smooth Vanilla Custard
Whisk the sugar, cornstarch, and salt together before adding the yolks. This helps distribute the cornstarch and makes it easier to work out lumps. Slowly whisk a cup of steaming milk into the yolk mixture, then return it to the saucepan with the remaining milk.
Keep the whisk moving across the bottom and into the corners as the custard thickens. Once it begins to bubble, take the pan off the heat and whisk in the vanilla and cold butter. If you see lumps, pass the warm custard through a fine-mesh sieve before assembling the slice.
How to Assemble and Slice
Line the pan with foil, leaving enough overhang to lift out the finished dessert. Set one pastry sheet in the bottom, spread the warm custard evenly over it, and place the second sheet on top. Press lightly so the pastry makes contact with the custard without squeezing the filling out at the edges.
Cover and chill for at least 4 hours, or overnight for easier slicing. Lift the dessert onto a cutting board and score the top pastry with a serrated knife before cutting all the way through. Wipe the blade between cuts and dust with powdered sugar just before serving.
Frequently Asked Questions
Can I use vanilla bean paste?
Yes. Use 2 teaspoons of vanilla bean paste in place of the seeds from one vanilla bean. Whisk it into the custard with the butter after taking the pan off the heat.
Can I make vanilla slice the day before?
Yes. Assemble it, cover it, and refrigerate overnight. The longer chill helps the custard hold its shape when cut. The pastry gradually softens where it touches the filling, so serve it the next day for the best balance of crisp pastry and firm custard.
How many pieces does an 8-inch pan make?
Cut three rows by three columns for nine generous squares, or four rows by four columns for 16 smaller portions.
Creamy Vanilla Slice Recipe Card
Two crisp layers of puff pastry filled with smooth vanilla bean custard and dusted with powdered sugar.
- Pastry bake time — 35–45 minutes per batch
- Chill time — At least 4 hours
- Yield — 9 large or 16 small squares
- Pan — 8-inch square
Ingredients
Pastry
- 2 sheets puff pastry, thawed
- Powdered sugar, for dusting
Vanilla Custard
- ⅔ cup (133 g) granulated sugar
- ½ cup (60 g) cornstarch
- ¼ teaspoon kosher salt
- 3½ cups (about 830 mL) whole milk
- 6 large egg yolks, at room temperature
- Seeds from 1 vanilla bean, or 2 teaspoons vanilla bean paste
- 4 tablespoons unsalted butter, cold and cubed
Instructions
- Preheat the oven to 400°F (200°C). Line two baking trays with parchment paper. Roll each puff pastry sheet into a roughly 9-inch square and prick it all over with a fork.
- Place each pastry sheet on a prepared tray. Cover with another sheet of parchment and weigh it down with a second baking tray. Bake for 35–45 minutes, checking around 30 minutes, until golden and crisp. Bake in batches if needed.
- Cool the pastry completely. Trim each sheet with a serrated knife to fit the inside of an 8-inch square pan. Line the pan with foil, leaving an overhang for lifting.
- Whisk the sugar, cornstarch, and salt together in a heatproof bowl. Add the egg yolks and whisk until evenly combined.
- Heat the milk in a saucepan over medium heat until steaming. Slowly whisk about 1 cup of the warm milk into the yolk mixture. Gradually whisk the tempered mixture back into the saucepan with the remaining milk.
- Cook over medium heat, whisking constantly, until the custard thickens and begins to bubble, about 5–7 minutes. Remove from the heat and whisk in the vanilla and cold butter until smooth. Strain if desired.
- Place one pastry sheet in the lined pan. Pour the warm custard over it and smooth the surface. Set the second pastry sheet on top and press gently to help it adhere.
- Cover and refrigerate for at least 4 hours or overnight. Lift out using the foil overhang, cut with a serrated knife, and dust with powdered sugar just before serving.