Nanaimo Bars

Ingredients

Base

• 115 g (½ cup) unsalted butter
• 50 g (¼ cup) caster sugar
• 30 g (⅓ cup) unsweetened cocoa powder
• 1 large egg, lightly beaten
• 200 g (2 cups) plain sweet biscuit crumbs (e.g., Marie/Graham crackers)
• 75 g (1 cup) desiccated coconut
• 60 g (½ cup) finely chopped walnuts or pecans (optional)
• 1 tsp vanilla extract
• Pinch of fine sea salt

Custard Buttercream

• 115 g (½ cup) unsalted butter, room temperature
• 240 g (2 cups) icing sugar, sifted
• 2 tbsp custard powder (traditional) or vanilla pudding mix
• 2–3 tbsp full-cream milk, as needed
• ½ tsp vanilla extract
• Pinch of salt

Chocolate Topping

• 200 g dark or semi-sweet chocolate, chopped
• 30 g (2 tbsp) unsalted butter or 1 tbsp neutral oil (for softer set)

Equipment

• 20 cm (8″) square pan
• Baking paper to line
• Heatproof bowl + saucepan (double-boiler setup)
• Electric hand mixer (for buttercream)
• Offset spatula

Method

1. Prepare pan. Line a 20 cm square pan with baking paper, leaving overhang for easy lift-out.
2. Cook base. In a heatproof bowl set over gently simmering water, melt butter with sugar and cocoa, stirring until glossy. Whisk in egg and cook 1–2 minutes, stirring, until slightly thickened (this gently cooks the egg). Remove from heat; stir in vanilla and salt, then the biscuit crumbs, coconut, and nuts until evenly coated.
3. Press & chill base. Firmly press mixture into the lined pan in an even layer. Chill 20–30 minutes until set.
4. Make custard buttercream. Beat butter until creamy. Add icing sugar, custard powder, vanilla, and salt; beat on low to combine. Add milk 1 tbsp at a time to reach a thick, spreadable frosting (it should hold lines). Spread evenly over the chilled base. Chill 20–30 minutes, until the surface is just firm to the touch.
5. Top with chocolate. Melt chocolate with butter (or oil) over a double boiler or in short microwave bursts; stir until smooth. Let cool 5–7 minutes until just warm (pourable but not hot). Pour over buttercream and tilt pan to level. Tap gently to release bubbles.
6. Score, then set. After 10–12 minutes, when the chocolate is beginning to set but not hard, lightly score cutting lines with a warm knife (prevents cracking later). Chill 1–2 hours until fully set.
7. Slice & serve. Lift out using paper. Cut into neat squares with a hot, dry knife (wipe between cuts). Store refrigerated in an airtight container up to 5 days; bring to room temp for the best texture.

Notes & Substitutions

• Egg-free base: Replace egg with 2 tbsp milk; do not heat as long—just until glossy and cohesive.
• Crumb options: Marie or Digestive biscuits (AU/UK) work like Graham crackers (US). Pulse to fine crumbs.
• Custard powder: Traditional flavour; if unavailable, use vanilla pudding mix plus a tiny pinch of turmeric for colour.
• Softer top layer: Butter or oil in the chocolate prevents an overly brittle set and cleaner slicing.
• Freezer-friendly: Wrap well and freeze up to 2 months; thaw in the fridge, then bring to room temp before serving.

Approx. Nutrition (per square, 1/20th)

~260 kcal • ~16 g fat • ~28 g carbs • ~3 g protein • ~80 mg sodium
Estimates only; varies with biscuit brand and chocolate percentage.

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