This Tim Tam Chocolate Custard Slice is a base of crushed Tim Tam biscuits, a layer of chocolate custard, crumbled Tim Tams and sweet puff pastry pieces. #timtams #custardslice
5 from 1 vote

Tim Tam Chocolate Custard Slice

Prep Time: 20 minutes
Cook Time: 20 minutes
Total Time: 40 minutes
Servings: 10 serves
Calories: 392kcal
Author: Marie Roffey
This Tim Tam Chocolate Custard Slice is a base of crushed Tim Tam biscuits, a layer of chocolate custard, crumbled Tim Tams and sweet puff pastry pieces.Note: This recipe requires 3 hours setting time
Course: Afternoon Tea, Dessert, Sweets
Cuisine: Australian



  • 215 g 11 Tim Tams, crushed
  • 50 g unsalted butter, melted

Chocolate custard

  • 150 g milk chocolate, finely chopped
  • 2 cups 500ml milk
  • 3/4 cup 180ml cream
  • 40 g unsalted butter
  • 1/2 cup caster sugar
  • 1/4 cup cocoa
  • 1 teaspoon vanilla extract
  • 1/2 cup cornflour
  • ¼ cup water
  • 3 egg yolks


  • 3 Tim Tams, extra
  • 1 sheet ready rolled puff pastry (10x10 inch)
  • 1 egg beaten
  • 1 tablespoon caster sugar (notes)
  • 1 tablespoon icing (powdered / confectioners) sugar (notes)
  • 1 tablespoon cocoa (notes)


For the Base

  • Grease and line an 8 inch spring form tin with baking paper.
  • Blitz the Tim Tams in a blender to crumbs. Add the melted butter and mix well. Tip the crumbs into the baking tin and, using lightly damp hands, press it firmly over the base. Place in the fridge until needed.

For the custard

  • Melt the chocolate in 30 second bursts in the microwave, stirring well between each until melted and smooth. This should not take more than 1 1/2 to 2 minutes.
  • Pour the milk & cream into a heavy based saucepan, and add the butter, sugar, cocoa and vanilla, then heat on very low heat until steaming, stirring regularly.
  • While the milk mixture is heating, mix together the water and cornflour until smooth. Pour it into a large bowl (or the bowl of a stand mixer) and add the egg yolks, then beat on high until light and pale yellow.
  • Once the milk mixture is steaming, remove from heat. Turn the stand mixer down to low-medium and pour the milk mix in a slow steady stream into the egg mix. Don’t pour it too quickly or the heat will scramble the eggs.
  • Once all the milk is added to the eggs, return the entire mix to the saucepan. Heat over low heat, stirring with a balloon whisk constantly, until it gets very thick. This will happen quite suddenly after about 5 minutes or so, so it’s important to keep gently whisking increasing intensity as it gets very thick. You will end up with lumpy custard if you don’t.
  • When the custard is very thick, remove from the heat and add the melted chocolate. Whisk until everything is smooth and well combined. The custard should be of a consistency that drops off the whisk in blobs (rather than running off in a stream).
  • Pour the custard over the Tim Tam base and tap to smooth out the top a little.
  • Allow to set in the fridge for 2-3 hours.

For the topping

  • Preheat oven to 220C / 200C fan forced.
  • Lay the puff pastry on a sheet of baking paper and prick all over with a fork, brush with beaten egg, then cut into squares (I found a pizza cutter the easiest mehod) - don't separate the pieces. Now, sprinkle over the sugar. Transfer to a baking tray. Bake for 15 minutes until golden and crispy.
  • Top the set custard with crumbled Tim Tams and cooled puff pastry pieces.
  • Dust with icing sugar, then dust with cocoa powder before serving.


  1. I use a standard Australian 20ml tablespoon (4 teaspoons worldwide)
  2. Make sure to allow for the 3 hours setting time