Preheat your oven to 350°F (180°C) and prepare a 9x13-inch baking pan.

In a food processor, combine flour, granulated sugar, and salt. Cut in cold butter until the mixture resembles coarse crumbs. Reserve 1½ cups of this for the topping and press the rest into the pan. Bake for 15 minutes.

Add brown sugar to the reserved crumb mixture and mix to form clumps. Set aside for topping.

In a bowl, whisk together granulated sugar, flour, cinnamon, and salt. Toss chopped peaches in this mixture. In another bowl, combine heavy cream and vanilla extract, then stir into the peach mixture.

Pour the peach filling over the warm crust and sprinkle the streusel topping on top. Bake for 45 minutes.

Cool the bars completely on a wire rack, then refrigerate for at least 2 hours before cutting into squares.