Vanilla Slice
An Australian bakery slice with crisp puff pastry, thick vanilla custard and a simple lemon icing.
Preparation: 30 min · Cooking: 45 min · Total: 5 hr 15 min · 9 servings
Ingredients
- 500 g ready-rolled puff pastry — Two sheets, kept cold; contains wheat and may contain milk.
- 75 g vanilla custard powder — Use instant-free cooking custard powder; check allergens.
- 10 ml vanilla extract — Pure vanilla extract.
- 750 ml whole milk — Keep refrigerated.
- 150 g caster sugar — Fine white sugar.
- 250 ml heavy cream — At least 35% fat; keep refrigerated.
- 40 g unsalted butter — Cut into small pieces.
- 120 g icing sugar — Sifted.
- 15 ml lemon juice — Freshly squeezed.
- 15 ml water — Add gradually to the icing.
Instructions
Prepare the pans and pastry
Heat the oven to 200°C conventional or 180°C fan. Line two baking trays and a 20 cm square pan with baking paper, leaving enough paper above the pan edges to lift the finished slice. Keep the milk and cream refrigerated until needed. Puff pastry, custard powder and icing sugar contain common allergens depending on brand, so check every label for wheat, milk, egg or soy.
Flatten and size the pastry sheets
Thaw the puff pastry only until flexible but still cold. Cut two squares about 22 cm wide so they can later be trimmed to the 20 cm pan. Put each square on a lined tray, prick all over with a fork, cover with another sheet of baking paper and place a second tray on top to keep it flat. Chill while the oven finishes heating.
Mix the custard slurry and line the pan
Put the custard powder in a bowl and whisk in 150 ml of the cold milk a little at a time until completely smooth. In the saucepan combine the remaining 600 ml milk, cream and caster sugar. Keep the vanilla and butter ready beside the stove. Line the base of the square pan with one baked pastry sheet after it has cooled and been trimmed to fit.
Bake the pastry with the retained timer
Bake the weighted pastry on the middle rack and start the retained 30-minute timer. At 20 minutes, carefully remove the upper tray and paper, then continue baking for up to 10 minutes until both sheets are evenly deep golden, dry and crisp. If they colour early, remove them before the timer ends. Use dry oven gloves because both trays are very hot. Cool completely on a rack, then trim each sheet to fit the pan.
The pastry is deep golden, dry and crisp; the cooked custard reaches at least 82°C and becomes ribbon-thick; after chilling, the centre is 5°C or below and holds its shape.
Bake the pastry sheets: 1800 seconds
Cook the custard and assemble the slice
Bring the milk, cream and sugar mixture just to a simmer over medium heat, stirring so the base does not scorch. Whisk the custard slurry again, pour it in slowly and whisk continuously. When thick bubbles break the surface, lower the heat and cook for 2 minutes, whisking, until the custard reaches at least 82°C and falls from the whisk in heavy ribbons. Remove from the heat and whisk in vanilla and butter. Immediately spread the hot custard over the pastry base, smooth it level and place the second pastry sheet on top. Take care: thick custard can spit and cause burns.
The pastry is deep golden, dry and crisp; the cooked custard reaches at least 82°C and becomes ribbon-thick; after chilling, the centre is 5°C or below and holds its shape.
Chill and check the set
Let the assembled slice stop steaming for no more than 30 minutes, cover without touching the pastry and refrigerate for at least 4 hours, preferably overnight. It is set when the centre is cold at 5°C or below and the custard holds its shape when the pan is gently tilted. If the centre is still soft or warmer than 5°C, continue chilling; do not slice it warm.
The pastry is deep golden, dry and crisp; the cooked custard reaches at least 82°C and becomes ribbon-thick; after chilling, the centre is 5°C or below and holds its shape.
Ice, portion and store safely
Mix the icing sugar with the lemon juice and add only enough water to make a thick, spreadable icing. Spread it over the cold top pastry and let it firm for 15 minutes. Lift the slice out by the paper. Use a serrated knife to saw through the top pastry first, then press a clean sharp knife through the custard to make 9 pieces. Serve chilled. Return portions to the refrigerator within 2 hours and store covered at 5°C or below for up to 3 days; this custard dessert should not be reheated or frozen.
Tips
- Bake the pastry between trays so the layers stay flat and easy to stack.
- Chilling overnight gives the cleanest slices; cut the brittle top pastry with a sawing motion first.
Common mistakes
- Warm pastry softens under the filling, so cool it completely before assembly.
- Custard powder must be dispersed in cold milk before heating or it will form lumps.
- Cutting before the centre is fully cold makes the custard run and the layers slide.
Substitutions
- For a plain finish, omit the icing and dust the cold top with a small amount of extra icing sugar just before serving.
Storage
Keep covered at 5°C or below and use within 3 days; return portions to the refrigerator within 2 hours.
Reheating
Do not reheat. Serve chilled; reheating melts the custard and softens the pastry.
About this recipe
Vanilla slice is an Australian bakery favourite related to the European custard slice. Its signature contrast is crisp pastry around a tall, cold vanilla-custard layer, often finished with icing.
Editorial approval does not establish independent kitchen testing. Check allergens and follow safe food handling.