Preheat oven to 350 F. Grease a 9-inch springform pan.
Pour 2½ cups cake batter into the pan (batter will be about 1 inch
high). Bake until golden and cooked through, about 25 minutes. Let cool
in the pan for 15 minutes, then remove and cool completely on a wire
rack. Use the remaining cake batter for cupcakes or extra cake.
Clean the springform pan and return cooled cake to the pan, top side
down. Line the inside edges of pan with a long strip of parchment that
extends at least 2 inches above the rim. Make sure the parchment sleeve
is tight against the cake edge so that cheesecake filling doesn’t run
down the sides. Tape parchment to secure. Transfer pan to the freezer
while preparing the filling.
In a medium mixing bowl, mix puree and fruit base, 134 g sugar and lemon juice until smooth; set aside.
In a large mixing bowl, beat cream cheese until very smooth. Add
Marshmallow Fluff and mix to combine. In a separate bowl, whip 174 g
heavy cream to firm peaks; stir into cream cheese mixture so there are
no lumps. Gently stir in blueberry mixture.
Remove cake from freezer and pour filling over the top. Return to freezer for 8 hours or overnight.