Butter an 8x8 pan and then line with parchment paper. Set aside. Make sure you leave an overhang of the parchment paper. You will use this to pull the bars out.Preheat oven to 350°.
Place all components of the crust into a food processor and pulse until coarse crumbs form. Once the crust holds together in clumps, press into the bottom of the pan, and slightly up the sides..Bake in 350° for about 20 minutes, until golden browned slightly caramelized.Cool completely on rack.
Filling
While the crust is baking and cooling, prepare the filling.Stir together peaches and peach preserves until well combined, set aside.With a hand mixer or a stand-up mixer, beat the cream cheese and sugar together until light and fluffy.Whisk in the sour cream and eggs. Then swirl in the peach mixture.
Smooth mixture over wafer crust and bake in 350° for 30 -35 minutes. The bars will still jiggle but should be slightly set. Let cool completely, about an hour, then place in refrigerator and chill for about 4 hours.
Using the the parchment overhang, lift he bars out of pan and cut into 2x2 bars.Sprinkle with powdered sugar just before serving and garnish with fresh mint leaves.