Ingredients
Equipment
Method
- Step 1: Prepare the raspberry compote: In a small saucepan, combine raspberries and sugar. Heat gently over low heat, mashing the fruit slightly with a fork. Dissolve the cornstarch in the cold water, then add the mixture to the saucepan. Mix well and cook for a few minutes, stirring constantly, until thickened. Remove from heat and let cool completely before assembling.
- Step 2: Concoct the white chocolate cream: In a large, very cold bowl, pour the very cold heavy cream and mascarpone. Whip on medium then high speed until the cream is thick and holds stiff peaks, like whipped cream. Meanwhile, melt the white chocolate (using a double boiler or gently in the microwave, stirring every 30 seconds). Let it cool slightly – it must not be hot when you add it. Gently pour the cooled white chocolate into the whipped cream mixture. Fold it in carefully with a spatula using up-and-down movements to keep the cream airy.
- Step 3: Assemble the lasagna: Find a square dish about 20x20 cm (or an equivalent rectangular dish). Line the bottom with a layer of Petit Beurre biscuits. Break them up slightly to fill the space. Spread a generous layer of the white chocolate cream over the biscuits. Then, add a layer of the cooled raspberry compote. Repeat the layers: biscuits, cream, compote... Continue until you run out of ingredients or fill the dish, making sure to finish with a layer of cream on top. Smooth the surface with a spatula.
- Step 4: Prepare the white chocolate ganache: In a small saucepan or microwave, heat the heavy cream for the ganache until just before boiling. Remove from heat and pour the hot cream over the white chocolate pieces in a heatproof bowl. Let sit for 1 minute without stirring. Then, gently mix with a small spatula or whisk until you have a smooth, shiny, and uniform ganache. Let it cool slightly (it should remain liquid but not be hot).
- Step 5: Pour the ganache over the top of the assembled lasagna and gently smooth it to cover the entire surface.
- Step 6: Chill: This is the hardest part! Place your masterpiece in the refrigerator for at least 2 hours. Ideally, 4 hours, or even better, overnight. This time is essential for the biscuits to soften and absorb moisture, and for the creams and compote to set perfectly for slicing.
- Step 7: Decorate and Serve: Just before serving, you can decorate the top of your lasagna. Chopped hazelnuts add a great crunch. You can also add a few fresh raspberries, white chocolate shavings, or a light dusting of powdered sugar. Let your imagination guide you!
Notes
Substitutions & Additions: Experiment with other fruits like mixed berries, blueberries, pitted cherries, or even a mango or peach compote. Instead of Petit Beurre, try Speculoos, Palmiers, Graham crackers, or ladyfingers. Replace white chocolate with milk or dark chocolate. Add crunch with toasted slivered almonds, pistachios, or chocolate chips. For an adult version, you can briefly soak the biscuits in milk flavored with rum, kirsch, or vanilla (be quick so they don't disintegrate!).
Tips for Success: Ensure all cream ingredients (bowl, whisk, cream, mascarpone) are very cold for best whipping results. The melted white chocolate folded into the cream must be cooled to avoid melting the cream. Chilling time (at least 2 hours, ideally 4 hours or overnight) is crucial for the biscuits to soften and the dessert to set. This lasagna is perfect to prepare the day before. Use a thin knife dipped in hot water and wiped clean between cuts for neat slices.
Storage: Store well-covered (plastic wrap touching the ganache surface, then a lid or more wrap) in the refrigerator for 2 to 3 days.
FAQ: Yes, frozen raspberries can be used – cooking will handle the excess water. Cream not whipping is usually due to insufficient coldness or low fat content cream (needs 30% M.G. minimum). Yes, the compote and cream can be made ahead and stored separately in the fridge. The sweetness is balanced by the raspberries; you can slightly reduce sugar in the compote if you prefer less sweet.