Heat oven to 350 degrees F. Grease 9-inch spring form pan.
In a bowl, sift together flour, salt and baking powder. Add yogurt; mix until well combined.
In a separate bowl, using an electric mixer, beat butter, 1 cup sugar and vanilla until light and fluffy. Add egg yolks, one at a time, beating well after each addition. Beat in flour mixture a little at a time; beat until well combined.
In a separate bowl, using an electric mixer, beat egg whites until stiff peaks form. Gently fold egg whites into batter.
Place 1/2 cup cocoa in a separate bowl. Pour boiling water over cocoa and whisk until all lumps are dissolved. Add bittersweet chocolate to cocoa and stir until melted. Gently fold chocolate mixture into batter.
Pour cake batter into pan. Batter should be about 1 inch high. Bake 25 minuets or until a toothpick inserted comes out clean. Remove and cool completely on wire rack.
Clean pan and return cooled cake to pan top side down. Line the inside edges of pan with a long strip of parchment paper that extends 2 inches above rim. Make sure parchment sleeve is tight against cake edge so cheesecake filling doesn’t run down side. Tape parchment to secure. Transfer pan to freezer while preparing filling.
Puree cherry tomatoes, 2/3 cup sugar and lemon juice in food processor until smooth; set aside. In a bowl, beat cream cheese until smooth. Mix in marshmallow fluff. In separate bowl, whip ¾ cup heavy cream until stiff peaks form; stir into cream cheese mixture. Gently fold in cherry tomato puree.
Remove cake from freezer and pour filling over top. Return to freezer for overnight (or at least 8 hours).
Several hours before serving, whip 1 ½ cups heavy cream, 2 tablespoons cocoa powder and 2 tablespoons sugar to soften peaks. Dollop on top of cake. Freeze again. Allow cake to sit at room temperature for 15 minutes before using a hot knife to slice and serve. Garnish top with halved cherry tomatoes dusted in sugar.