Chelsea Tart Recipe

Make pastry

In a bowl or food processor combine flour, icing sugar and salt. Rub in or pulse in cold cubed butter until mixture resembles coarse breadcrumbs with pea-sized butter pieces remaining.

Add the egg yolk and 2 tablespoons cold water. Mix quickly until dough just comes together. Do not overwork. Press into a disk, wrap in cling film and chill in the refrigerator for at least 30 minutes.

Roll out the chilled dough on a lightly floured surface to about 3 mm (1/8 inch) thickness and use to line a 9-inch (23 cm) tart tin with removable base. Trim excess and chill again for 15 minutes.

Preheat oven to 375°F (190°C). Line the pastry with parchment and fill with baking beans or rice. Blind bake for 15 minutes, remove weights and parchment, then bake 6–8 minutes more until the base is pale golden. Brush the base with apricot jam if using, and allow to cool while preparing filling.

Reduce and caramelise whey

Place the 2 cups whey and 1 cup granulated sugar in a wide, heavy saucepan over medium heat. Stir gently until sugar dissolves, then bring to a steady simmer. Reduce heat to medium-low and simmer, stirring occasionally, until the liquid reduces and deepens to an amber/golden caramel color and has a noticeably syrupy consistency — about 25–35 minutes. Watch carefully in the final stages to avoid burning.

Once reduced and caramel-coloured, remove from heat and whisk in 2 tablespoons unsalted butter, 1/2 cup heavy cream and the 2 egg yolks tempered: to temper, whisk a ladle of the hot caramelised whey into the egg yolks quickly, then return the warmed yolks into the pan while stirring constantly. Stir in 1 teaspoon vanilla and 1/4 teaspoon salt. If mixture seems grainy, warm gently and whisk until smooth. If it is too thin, return to low heat and stir until it reaches a thick custard-like consistency (coats the back of a spoon). Cool slightly.

Pour the warm caramelised whey filling into the cooled blind-baked tart shell. Smooth the top and sprinkle 1 tablespoon demerara or caster sugar evenly over the surface. Optionally torch the sugar briefly to create a light caramelised crust. Chill the tart in the refrigerator for at least 2 hours to set.

Make custard base

In a medium saucepan, combine 2 cups whole milk, 1/2 cup heavy cream, 2 tablespoons milk powder (if using) and 1/2 cup sugar. Warm over medium heat until the sugar dissolves and the mixture is hot but not boiling.

In a bowl, whisk 3 egg yolks. Temper the yolks by slowly whisking in 1/3 of the hot milk mixture. Then return the tempered yolks to the saucepan, stirring constantly over low heat until the custard thickens slightly and coats the back of a spoon (170–175°F / 77–80°C). Do not boil.

Remove from heat. Stir in 1 teaspoon vanilla and 1/8 teaspoon salt. Strain the custard through a fine-mesh sieve into a clean bowl, cool to room temperature, then cover and chill in the refrigerator for at least 4 hours or overnight.

Churn and freeze

Churn the chilled base in an ice cream machine according to manufacturer’s instructions until it reaches a soft-serve consistency. Transfer to a lidded container and freeze for at least 2–4 hours to firm up before serving.

Remove the tart from the tin and place on a serving plate. If you brushed apricot jam earlier, the tart top will have a slight sheen; if not, you can brush lightly with warmed jam now for shine.

Slice the tart and serve each slice with a scoop of the milk ice cream. For extra presentation, sprinkle a little flaky sea salt over the ice cream or tart, and optionally torch the tart sugar again at the table for show.

Leftovers: keep the tart chilled; the ice cream should be stored in an airtight container in the freezer.