For the shortbread crust: Preheat the oven to 350 degrees. Line a 13 x 9 in baking dish with foil, then grease the foil on all sides. In the bowl of an electric mixer, beat the butter until it begins to soften, about 30 seconds. Add sugar and salt and beat on low speed until just combined. Add the flour and beat on low speed until incorporated then increase to high speed and beat until a cohesive dough is formed. Using your fingers, press the dough into the baking dish and bake for 20 minutes or until puffy and golden brown.

For the filling: Spread peach jam evenly over the crust, then layer with sliced peaches. To make the cream layer, beat cream cheese and sour cream on high speed until smooth. Add sugar and 1 Tablespoon flour and beat another 30 seconds. Add eggs and vanilla and beat until smooth and thoroughly combined. Pour cheesecake mixture over peach slices. Set aside.

For the topping: In a small bowl, combine flour, sugars, ginger, cinnamon, and salt. Pour melted butter over all and use your fingers to mix together until coarse crumbles form. Sprinkle over the top of the cheesecake layer. Bake again at 350 for 30 minutes or until crumbles are golden brown and center is set.