Step 1: Prepare the Chocolate Sponge Cake

1. Preheat the Oven: Set to 350°F (175°C). Grease and line an 8-inch (20cm) round cake pan.
2. Whisk the Eggs and Sugar: Beat eggs and sugar until pale and fluffy.
3. Combine Dry Ingredients: Sift together flour, cocoa powder, and baking powder.
4. Mix Wet and Dry Ingredients: Gently fold the dry ingredients into the egg mixture. Add vanilla extract, milk, and oil, stirring until smooth.
5. Bake: Pour the batter into the pan and bake for 15-18 minutes or until a toothpick inserted in the center comes out clean.
6. Cool: Let the sponge cool completely before assembling.

Step 2: Prepare the Raspberry Mousse

7. Cook the Raspberries: In a saucepan, heat raspberries, sugar, and lemon juice over medium heat until soft. Blend and strain to remove seeds.
8. Bloom the Gelatin: Sprinkle gelatin over 3 tablespoons of water and let it sit for 5 minutes.
9. Combine with Raspberry Puree: Warm the raspberry puree slightly and mix in the bloomed gelatin. Let cool.
10. Whip the Cream: Beat chilled heavy cream until soft peaks form.
11. Fold the Mixture: Gently fold the raspberry mixture into the whipped cream.

Step 3: Assemble the Entremet

12. Prepare the Cake Ring: Place the cooled chocolate sponge at the base of an 8-inch cake ring or springform pan.
13. Add the Mousse Layer: Pour the raspberry mousse over the sponge, smoothing the top with a spatula.
14. Chill: Refrigerate for at least 2 hours until set.

Step 4: Prepare the Chocolate Ganache

15. Heat the Cream: In a saucepan, bring heavy cream to a simmer.
16. Melt the Chocolate: Pour the hot cream over the chopped dark chocolate, let sit for 2 minutes, then stir until smooth.
17. Add Vanilla: Mix in vanilla extract.
18. Spread Over Mousse: Once the raspberry mousse is set, pour the ganache over it and smooth it out.
19. Chill Again: Refrigerate for at least 1 hour.

Step 5: Prepare the Mirror Glaze

20. Bloom the Gelatin: Sprinkle gelatin over 3 tablespoons of water and let sit for 5 minutes.
21. Heat the Glaze Base: In a saucepan, heat sugar, water, glucose syrup, and condensed milk until hot but not boiling.
22. Add Chocolate and Gelatin: Remove from heat, stir in white chocolate and bloomed gelatin. Mix until smooth.
23. Color the Glaze: Add pink or red food coloring if desired.
24. Cool the Glaze: Let it cool to 95°F (35°C) before pouring.

Step 6: Glaze and Final Assembly

25. Unmold the Entremet: Remove the cake from the ring.
26. Pour the Mirror Glaze: Place the cake on a wire rack and pour the glaze evenly over the top. Let excess drip off.
27. Chill Again: Refrigerate for at least 1 hour before serving.