Preheat the oven to 350°F. Prepare a 9-inch springform pan with parchment paper and grease the sides. Mix the dry ingredients for the cake, add wet ingredients, and bake for 18-20 minutes until a toothpick comes out clean. Let the cake cool completely.

Make the cheesecake filling: beat cream cheese, sugar, and flour until smooth. Add sour cream and vanilla. Mix in eggs one at a time. Pour over cooled cake layer, then bake in a water bath at 300°F for 1 hour 15 minutes. Cool and refrigerate.

Prepare the chocolate ganache: heat heavy cream and pour over chocolate chips, add corn syrup and vanilla, whisk until smooth. Cool completely. Make pastry cream by cooking milk, sugar, cornstarch, and eggs until thickened. Add butter and vanilla, then cool.

Assemble the dessert: pipe ganache around the edge of the cheesecake, spread pastry cream in the center, then chill until ready to serve.