Healthy chocolate tart

1 Reserve 2 teaspoons of the flour, then put the rest with the spread into a bowl and rub into fine crumbs. Sift in the cocoa and icing sugar, then use a round-bladed knife to mix in the oil, egg yolk and 1½– 2 tablespoons cold water. Gently gather into a ball, then roll out on a lightly floured surface to fit a 20cm diameter, 3.5cm deep loose-bottomed flan tin. Ease the pastry into the tin, leaving a slight overhang. Lightly prick the base, then chill for about 10 min.

2 Preheat the oven to 190°C/fan 170°C/gas 5. Put the flan tin on a baking sheet, line the pastry with foil and fill with baking beans. Blind-bake for about 15 min until firm. Remove the beans and foil, then bake for another 10 min or until cooked. Remove from the oven and trim the edges with a sharp knife. Leave to go cold.

3 To make the filling, put the chocolate in a heatproof bowl (large enough to sit over a pan of water without touching the water). Mix the cocoa, coffee and vanilla extract with the milk and pour the liquid over the chopped chocolate. Now put the bowl over a pan of gently simmering water, stir, then immediately take the pan off the heat but keep the bowl sitting on the pan. Leave, stirring occasionally, until the chocolate mixture is fully melted. Stir in 2 tablespoons boiling water, then take the bowl off the pan and leave to cool slightly.

4 Whisk the egg whites into stiff peaks, then whisk in the sugar until thick and glossy. Fold the crème fraîche into the cooled chocolate mixture. Fold one-third of the egg whites into the chocolate mixture using a large metal spoon, then gently fold in the remaining whites, a third at a time, until evenly mixed in. Remove the pastry case from the tin and put on a serving plate. Spoon the filling into the case, smoothing out evenly. Chill for about 3 hr, or overnight.