1. Preheat your oven to 350°F or 175°C.

2. In a large bowl, whisk together 250g or 2 3/4 cups of flour, 60g or 1/2 cup of cocoa powder, and 60g or 1/4 cup of vanilla sugar until well combined.

3. Add 115g or 1/2 cup of softened butter to the dry ingredients and mix until the dough comes together in a cohesive mass.

4. Press the dough into a 23cm or 9-inch tart pan with a removable bottom, making sure to evenly cover the entire surface.

5. Bake the tart crust in the preheated oven for 20 minutes, then let it cool completely on a wire rack.

6. In a separate bowl, whip 3 large eggs and 200g or 1 cup of granulated sugar until stiff peaks form and the mixture becomes light and airy.

7. Melt 250g or 1 cup of dark chocolate in a double boiler or in the microwave in 30-second increments, stirring between each interval until the chocolate is smooth and glossy.

8. Fold the egg mixture into the melted chocolate until the two are well combined and no streaks of egg remain.

9. Pour the chocolate mixture into the cooled tart crust, smoothing the top with a spatula.

10. Refrigerate the tart for at least 2 hours or overnight to allow the filling to set.

11. Just before serving, top the tart with fresh raspberries and sliced mango, arranging them in a decorative pattern. If desired, garnish with edible flowers and chocolate Easter eggs for a festive touch.