For Brownie Batter: Sift flour, cocoa, baking powder and salt in medium bowl; set aside. Beat eggs, sugars and water in bowl of mixer fitted with paddle attachment until well blended. Mix in butter. Add dry ingredients. Mix just until combined, scraping side of bowl as needed. Stir in TOBLERONE. Spoon batter into 9-inch parchment paper-lined springform pan.
Bake in 350°F standard oven 25 min. or until set. Cool completely in pan on wire rack.
For Cheesecake Batter: Beat cream cheese in bowl of mixer fitted with paddle attachment on low speed until smooth. Scrape side of bowl; beat on medium speed until well blended. Add sugar; mix until blended.
Combine whole eggs and egg yolks in small bowl. Gradually add to cream cheese mixture, scraping side of bowl after each addition. Mix in cream and vanilla. Stir in TOBLERONE just until combined. Pour over cooled Brownie Batter layer.
Wrap bottom of pan with foil to prevent Brownie from getting soggy. Place pan in water bath in 350°F standard oven. Bake 45 min. or until center of cheesecake no longer jiggles. Cool completely in pan on wire rack. Refrigerate several hours or overnight.
For Soft Ganache: Place 7 oz. TOBLERONE in large bowl. Bring cream just to boiling. Remove from heat and pour over TOBLERONE in bowl. Let stand until chocolate softens. Blend with immersion blender. Scrape side and bottom of bowl, then blend another 15 seconds. Chill several hours or overnight. When ready to use, whip in bowl of mixer fitted with whisk attachment until medium peaks form. Spoon into pastry bag fitted with #5 round tip.
Remove chilled cake from springform pan. Pipe small mounds of Soft Ganache over entire top of cake. Sprinkle with remaining 2 oz. TOLBERONE. Refrigerate until ready to serve.