Use a digital candy thermometer or your boyfriend’s multimeter for this recipe. Not only do you need it to make the Italian meringue, it’s also important to combine the different components of the mousse at the right temperature (26°C/78°F). Also, make sure to read through the instructions first and measure all the ingredients before starting with the recipe.


  • 200g (or 7 ounces) buttery cookies, such as shortbread
  • ¼ teaspoon lemon zest
  • 400g (about 14 ounces) fresh strawberries, washed and hulled
  • ½ tablespoon lemon juice
  • 225ml (or ¾ cup + 3 tablespoons) heavy whipping cream (at least 35% fat)
  • enough sheet gelatin to firmly set 645ml (or 2½ + 3 tablespoons) of liquid*
  • 100g (or ½ cup) granulated sugar
  • 3 tablespoons of water
  • 2 large egg whites (about 65mls)
  • pinch of salt
  • 100g (or ½ cup) granulated sugar
  • 240ml (or 1 cup) water
  • 5 long stalks of rhubarb, preferably red stalks


  1. First, preheat your oven to 175°C/350°F (standard oven setting) and line the sides of a 20-cm/7-inch spring form pan with strips of baking parchment. Use a little butter to help stick the parchment to the sides of the pan.
  2. Next, place the cookies in a sturdy Ziploc bag and crush them with a rolling pin or the back of a spoon. The finer the crumbs, the better the crust will hold its shape.
  3. Pour the fine cookie crumbs into a small bowl and add the lemon zest. Rub the lemon into the crumbs using your fingers (should take about a minute).
  4. Press the lemony crumbs evenly into the prepared spring form pan and bake the crust for about 10 minutes, or until it has turned a light golden brown. Remove from the oven and allow the crust and the pan to cool to room temperature.
  5. Place the strawberries in a blender and blend until completely smooth. Add the lemon juice and pulse briefly to combine.
  6. Place a fine-meshed strainer over a measuring jug and pour the strawberry purée through the strainer into the jug. Discard the seeds left in the strainer (or stir into yogurt!).
  7. Measure off 325ml (or 1½ cup + 1 teaspoon) smooth strawberry purée. Eat the rest. Place in the fridge until needed.
  8. In a large bowl, whip the cream to very soft peaks by hand. You don’t want to use a mixer for this, as the use of a mixer can weaken the structure of the finished whipped cream. Because the whipped cream ensures that the mousse cake is light and fluffy, you want to make sure it’s strong enough to hold the weight of the other ingredients.
  9. Once the cream has been whipped to very soft peaks, place it in the fridge until use.
  10. Fill a medium-sized bowl or a large measuring jug with cold water and carefully submerge the gelatin sheets into the water, one at a time. Allow the gelatin to soak for 10-15 minutes (or soak according to the manufacturer’s instructions).
  11. In the meantime, combine the sugar and water in a small saucepan. Heat over low heat, stirring with a metal spoon until the sugar has dissolved.
  12. Once the sugar has dissolved, crank the heat up to medium-high and stop stirring. Clip a sugar thermometer onto the side of the pan.
  13. Once the sugar syrup is cooking, combine the egg whites and salt in a medium-sized, heatproof bowl. Using a mixer fitted with the whisk attachment, whip until the whites are frothy.
  14. Stop mixing and closely monitor the temperature of the sugar syrup. As soon as the syrup reaches a temperature of 113°C/235°F take the pan off the heat and start whipping the egg whites again. Carefully pour the hot sugar syrup into the bowl with the egg whites, mixing continuously to prevent the eggs from scrambling. Try not to pour the syrup onto the whisk; otherwise the hot syrup may splatter against the sides of the bowl (or into your face!).
  15. Once all the syrup has been added, keep mixing until the bottom of the bowl feels cool to the touch. This should take about 8 minutes and your meringue should cool down to about 26°C/78°F. Set aside.
  16. To a small saucepan, add about 120ml (or ½ cup) strawberry purée. Heat gently until hot, then take the pan off the heat.
  17. Squeeze the excess water out of the gelatin and add the gelatin sheets to the strawberry purée on at a time. Make sure to stir the mixture after each addition to make sure the gelatin melts properly. If the gelatin doesn’t melt properly anymore (this could happen, because the cool gelatin sheets bring the temperature of the mixture down), place the pan back on a very low heat, stirring continuously until the gelatin has melted. Make sure to never cook the gelatin, because it won’t set if you do!
  18. Once all the gelatin has been melted into the strawberry purée, add the gelatin mixture to the remaining strawberry purée. Stir to combine, then check the temperature of the mixture. If necessary, allow to cool to 26°C/78°F.
  19. Whisk one third of the meringue into the strawberry purée. I know this sounds weird, but folding it in doesn’t work. There will still be lumps of meringue
  20. Repeat with the remaining two thirds of meringue, but this time, fold the meringue into the strawberry purée with a rubber spatula. If you have trouble getting rid of all the lumps, whisk briefly.
  21. Take the very softly whipped cream out of the fridge and whip again, by hand, until the cream holds soft peaks. Gently fold the fruit mixture into the whipped cream, a few spoonfuls at a time.
  22. Once all of the fruit mixture has been added, the mixture should be smooth, light and fluffy.
  23. Check the temperature of the cookie crust and spring form pan, to make sure both have cooled completely. If so, pour the mousse mixture on top of the crust. Smooth the top of the mousse with a spatula, cover with plastic wrap and place in the fridge to set overnight.
  24. Remove the spring form collar from the cake and peel away the strips of baking parchment. Carefully transfer the cake to a serving platter.
  25. In a small saucepan, combine the water and sugar. Heat over low heat, stirring with a metal spoon until the sugar has dissolved. Once the sugar has dissolved, stop stirring and allow the syrup to continue heating over low heat. Lay out sheets of paper towels on your counter.
  26. Using a v-shaped vegetable peeler shave the rhubarb stalks into long strips. Make sure the strips aren’t too thin. I found that the thicker strips were easier to work with and held their shape much better than the thinner strips.
  27. Once the sugar syrup comes to a boil, add the rhubarb strips to the simmering syrup, one or two at a time. Cook the strips for about 20-30 seconds, then remove them from the pan with two forks (if one end of the strip touches the other end, the ends will stick together and you won’t be able to unstick them, so be careful!).
  28. Lay the cooked rhubarb strips flat onto the paper towels to drain.
  29. Once all the strips have been cooked, carefully arrange them on top of the mousse cake and, using a pair of scissors, trim away the excess. The strips will stick naturally. Place the cake in the refrigerator until ready to serve.
  30. Cake can be stored, covered, in the fridge for two days.
  31. To cut the cake, I first carefully cut through the candied rhubarb with scissors, before cutting the cake with a sharp knife.

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