Preheat oven to 350°F (180°C) and grease a 9x13-inch pan. Combine flour, sugar, and salt. Cut in cold butter until mixture resembles coarse meal. Set aside 1½ cups for topping, press remaining into pan and bake for 15 minutes.

While crust bakes, mix reserved crumb mixture with brown sugar. Form clumps for streusel topping and set aside.

In a bowl, whisk together sugar, flour, cinnamon, and salt. Fold in chopped peaches. In another bowl, whisk cream and vanilla, then pour into peach mixture and combine well.

Pour peach filling over baked crust, spreading evenly. Sprinkle crumb topping over filling. Bake for about 45 minutes until topping is golden brown and juices are bubbling.

Allow bars to cool in the pan on a wire rack for 2 hours before cutting. Serve warm with vanilla ice cream.