Prepare the sponge cake:

Preheat the oven to 410°F. Line a baking sheet with buttered parchment paper.

In a mixing bowl, beat the egg whites with a pinch of salt until stiff peaks form.

Add the egg yolks, then the granulated sugar, flour, cornstarch, and cocoa powder. Mix quickly.

Pour the batter onto the baking sheet and bake for about 10 minutes.

Turn the sponge cake out onto a damp kitchen towel and roll it up. Let it cool.

Peel the pear, remove the seeds, and cut it into quarters.

In a saucepan, melt the sugar in the water and bring to a boil. Keep boiling for 5 minutes. Add the pear quarters to the syrup and poach for 5 to 6 minutes.

Let cool. Drain the pear pieces and cut them into small cubes.

Unroll the cake and spread a layer of chocolate mousse over it. Top with diced pear and candied peanuts. Roll up the cake and wrap it tightly in plastic wrap. Chill for at least 4 hours.