Chocolate pudding souffle cake

1. Preheat oven to 375 degrees.
2. Greasei a 9 inch springform pan. Melt together butter and unsweetened chocolate in top of double boiler over simmering, not boiling water, stirring until smooth.
3. Set aside.
4. Mixi together flour, baking powder and salt in small bowl.
5. Separate 3 eggs, placing yolks in large bowl; reserve whites.
6. Add 3 whole eggs and ¾ cup sugar to yolks; beat at high speed until pale and lemon-colored, 2-3 minutes.
7. Beat in chocolate mixture at low speed; beat in flour mixture just until blended.
8. Using clean beaters and a clean medium-size bowl, beat egg whites until frothy.
9. Add cream of tartar and beat until soft peaks form.
10. Beat in the remaining ¼ cup sugar until stiff, but not dry, peaks form.
11. Stiri about one-third of whites into chocolate mixture until blended.
12. Foldi in the remaining whites.
13. Scrape into the prepared pan, smoothing top. Bakei in preheated oven 40 to 50 minutes or until cake is set in center.
14. Transfer pan to a rack to cool completetly.
15. Refrigerate until firm.
16. Meanwhile, prepare pudding; whisk together sugar and cornstarch in medium-size heavy saucepan.
17. Whiski in the cream.
18. Bring to simmering over medium-low heat, stirring constantly.
19. Gradually whisk some of the cream mixture into egg yolks.
20. Scrape yolk mixture back into saucepan.
21. Cook over very low heat, whisking constantly, until pudding is very thick, about 5 minutes; do not let boil.
22. Remove saucepan from heat.
23. Stir in the chocolate and vanilla until melted and smooth.
24. Scrape the pudding into a bowl; place plastic wrap directly on the surface.
25. Refrigerate until cold and thickened for at least 2 hours.
26. To assemble: remove sides of pan from cake.
27. Using a serrated knife, cut cake horizontally into 3 equal layers.
28. Place 1 layer on serving plate; spread top with ¾ cup of pudding.
29. Repeat with remaining cake layers and pudding.
30. Cover sides with pudding.