Master this elegant French-inspired dessert with layers of silky chocolate ganache on a crisp almond biscuit base, chilled to perfection and served atop smooth vanilla custard.
Make the biscuit: Preheat the oven to thermostat 5 (150°C). In a bowl, combine the sugar and powdered almonds. Whip the egg whites to stiff peaks and gently fold into the almond mixture.
Butter a baking sheet (or use a Silpat mat), spread the batter evenly with a spatula, and bake for 15 minutes. Remove from the oven, peel off the biscuit, and cool on a wire rack.
Prepare the filling: Break each type of chocolate into pieces separately. Divide the cream: 10 cl into one saucepan with the white chocolate, 10 cl into another with the praline milk chocolate, and the remaining cream into a third with the dark chocolate.
Melt each chocolate mixture over low heat, stirring until smooth, then let cool.
Cut the cooled biscuit into four rectangles sized to fit your cake mold (about 21 cm x 9 cm).
Assemble in the mold: Layer a biscuit rectangle, spread with dark chocolate cream; add another biscuit, spread with white chocolate cream; add a third biscuit, spread with praline cream; top with the final biscuit. Press gently, cover with cling film, and refrigerate for at least 12 hours.
To serve: Spoon vanilla custard onto plates, add a slice of terrine. Dot with melted dark chocolate and drag the tip of a knife through the dots to create artistic swirls.
