Instructions:

1. Preheat oven to 180 degrees Celsius.
2. Grease a springform pan (26 cm diameter) with butter and line the base with parchment paper.
3. In a large bowl, cream together soft butter and sugar until smooth.
4. Add eggs one at a time and beat well.
5. Mix flour and cocoa powder in a separate bowl.
6. Gently fold the flour-cocoa mixture into the butter-egg mixture.
7. Pour the batter into the prepared springform pan and bake for about 25 minutes, or until a toothpick inserted comes out clean.
8. Let the sponge cake cool completely.
9. Peel, core, and thinly slice the ripe pears.
10. Toss the pear slices with lemon juice.
11. Heat the fruit juice in a small saucepan over medium heat.
12. Add sugar to the fruit juice as desired and bring to a boil.
13. Reduce heat and stir in the vegetable gelling agent.
14. Simmer for a few minutes until the sauce thickens.
15. Cut the cooled sponge cake horizontally (optional).
16. Place the first layer on a serving plate, top with pear slices, and drizzle with some chocolate sauce.
17. Cover with the second sponge cake layer.