- With the rack in the middle position, preheat the oven to 350°F (180°C). Line the bottom of an 8-inch (20 cm) springform pan with removable bottom with parchment paper. Do not butter the sides.
- In a bowl, whisk the eggs, sugar, vanilla and salt with an electric mixer until the mixture triples in volume and falls from the beaters in a ribbon, about 10 minutes. With the machine running on low speed, drizzle in the melted butter. Using a whisk, gently fold in the flour. Spread the mixture out in the prepared pan.
- Bake for 35 minutes or until a toothpick inserted in the centre of the cake comes out clean. Let cool completely on a wire rack, about 3 hours. Pass a thin blade between the side of the pan and the cake to unmould.
- Meanwhile, in a pot off the heat, whisk together the sugar and cornstarch. Add the eggs and whisk until smooth. Add the strawberry purée and lemon juice. Bring to a boil over medium heat, whisking constantly and scraping the bottom and sides of the pot, until the mixture thickens. Let simmer for 1 minute. Pour into a bowl. Cover with plastic wrap directly on the surface of the cream and refrigerate for 3 hours or until completely chilled.
- In another bowl, whisk the cream with an electric mixer until stiff peaks form. Using a whisk, add one-third of the whipped cream to the chilled strawberry mixture. Gently fold in the remaining whipped cream.
- Cut the cake in half horizontally to get two layers. Wash out the springform pan and place one cake layer in the bottom. Top with the strawberry mousse. Cover with the second cake layer. Refrigerate for 12 hours.
- In a bowl, whisk the cream and sugar with an electric mixer until stiff peaks form. Transfer into a pastry bag.
- Decorate the cake with rosettes and dollops of whipped cream, alternating a star and plain tip. Garnish with the strawberries and, if desired, thyme leaves.
To quickly bring your eggs to room temperature, plunge them in a bowl of hot water (not boiling) for 10 minutes. Room temperature eggs whip up more easily and will give your cake almost 50% more volume than cold eggs.
To get ¾ cup (180 ml) strawberry purée, blend 1 ½ cups (210 g) fresh or thawed frozen strawberries in a blender until smooth. Strain through a sieve.