- Preheat the oven to 350°. In a medium bowl, melt the chocolate in a micro-wave oven at medium-high speed, stirring at 30-second intervals until smooth. Whisk in the butter until fully incorporated; let the mixture cool slightly.
- In a large bowl, whisk the 3 egg yolks with the whole egg and 1/3 cup of the sugar until blended. Add the melted chocolate and vanilla and whisk until smooth.
- In a medium bowl, beat the 3 egg whites with an electric mixer until soft peaks form. Add the remaining 1/3 cup of sugar, 1 tablespoon at a time, beating for 10 seconds between additions. Continue beating at medium-high speed until the whites are firm and glossy. Whisk one-quarter of the meringue into the chocolate mixture until well blended. Gently fold the remaining meringue into the chocolate mixture just until no white streaks remain.
- Scrape the chocolate soufflé mixture into an ungreased 9-inch glass pie plate. Gently shake the pie plate to smooth the surface and bake for about 35 minutes, or until the soufflé is cracked and no longer wobbles. Transfer the soufflé to a wire rack to cool.
- Meanwhile, line a large plate with plastic wrap and freeze until well chilled. Scoop ice cream balls onto the chilled plate and freeze them. If necessary, soften the ice cream in the refrigerator for 15 minutes before scooping.
- Set the ice cream balls on the soufflé, mounding them in the center. Drizzle with 1/4 cup each of Caramel Sauce and Chocolate Sauce, cut into wedges and serve right away. Pass the remaining sauce at the table.
The chocolate soufflé crust can be baked up to 1 day ahead; cover with plastic wrap and let stand at room temperature.