In a medium bowl, mix sifted flour, baking powder and salt.
In a large bowl, combine ¾ cup white sugar, melted butter, and egg, and, using electric mixer, beat on medium-high speed until light and fluffy - 1 or 2 minutes.
Reduce speed to medium, then mix in milk, vanilla just until combined.
Keeping the mixer speed low, mix in flour mixture, gradually, just until combined. Do not over mix.
Fold in half the apples and half the peaches into the batter. Do not fold in blueberries in the cake batter.
Pour the cake batter into the parchment paper lined springform pan. Spread blueberries, remaining apples and peaches over the top of the cake. Top with the crumb topping - it should cover all the fruit.
Bake about 45 minutes or until the tester inserted in the center of the cake comes out clean.
Let cool in springform pan on a wire rack. After cake has cooled for about 40 minutes, release the cake from the springform pan. At this point, if the cake is cool enough, you can slide your hand under the cake, between the parchment paper and the bottom of the pan ,and move the cake with the parchment paper attached to its bottom onto a cake plate easily.