Custard Recipe

Preheat the oven to 170°C (340°F). Line a 20 x 20 cm (8 x 8 in) square baking pan with parchment paper, leaving a 2–3 cm overhang to lift the brownies out easily. Position a rack in the middle of the oven.

Melt chocolate and butter

Combine the chopped chocolate and butter in a heatproof bowl set over a pot of barely simmering water (double boiler) or in short bursts in the microwave (20–30 seconds, stirring between). Stir until smooth and glossy. Remove from heat and let cool 3–5 minutes.

Mix sugar and eggs

Place the granulated sugar and whole eggs in a medium bowl. Whisk vigorously until combined, slightly thickened and pale — about 1–2 minutes by hand. Stir in the vanilla extract.

Combine chocolate and egg mixture

Pour about one-third of the melted chocolate into the egg-sugar mixture and whisk quickly to temper and incorporate. Add the remaining chocolate and stir until homogeneous.

Fold dry ingredients

Sift the flour, cocoa powder and salt over the chocolate mixture. Using a rubber spatula, gently fold until just combined and no streaks of flour remain. Do not overmix.

Bake brownie layer

Scrape the batter into the prepared pan and smooth the top evenly. Bake 18–22 minutes — the center should be set but still fudgy (a toothpick inserted will have moist crumbs). Remove from oven and let rest while you prepare the custard; the surface will be slightly domed and glossy.

Heat milk and cream

In a medium saucepan, combine the whole milk, heavy cream and 25 g of the sugar (reserve remaining sugar for yolks). Warm over medium heat until steam rises and small bubbles form around the edges; do not boil. Remove from heat.

Whisk yolks and sugar

In a bowl, whisk the egg yolks, whole egg, the remaining 25 g sugar and cornstarch (if using) until smooth, pale and slightly thickened, about 30–45 seconds.

Temper eggs and combine

Slowly pour about one-third of the hot milk mixture into the egg mixture in a thin stream while whisking constantly to temper the eggs. Then pour the tempered egg mixture back into the saucepan with the remaining milk, whisking to combine.

Cook custard to nappe

Return the saucepan to low–medium heat and cook, stirring constantly with a heatproof spatula or wooden spoon, until the custard thickens enough to coat the back of the spoon (nape) and reaches about 80–82°C (175–180°F) if using a thermometer — about 3–5 minutes. Do not let it boil. Remove from heat and stir in the vanilla extract.

Strain and cool slightly

Pour the custard through a fine-mesh sieve to remove any cooked egg bits into a bowl. Let it cool for 5 minutes, stirring occasionally to release steam and prevent a skin from forming.

Lower oven temperature to 160°C (320°F). Pour the warm custard evenly over the baked brownie layer in the pan — pour slowly to allow custard to settle into any cracks. Gently tap the pan on the counter to level the surface and remove air bubbles.

Bake the combined dessert at 160°C (320°F) for 20–25 minutes, or until the custard is set at the edges but slightly wobbly in the center (it will continue to set as it cools). If you prefer a firmer custard, bake up to 30 minutes.

Remove from oven and let cool on a wire rack for 1 hour, then refrigerate for at least 2 hours (preferably 4 hours or overnight) to fully set and make slicing neater.

Use the parchment overhang to lift the chilled brownie-custard slab from the pan. Trim the edges for neat squares if desired. Dust lightly with cocoa powder and scatter a few sea salt flakes over each piece if using.

Slice into 9 equal squares (3 x 3). Serve chilled or at cool room temperature. Store any leftovers covered in the refrigerator for up to 4 days.