Preheat oven to 350°F. Line a 9x13 inch baking pan with parchment paper, leaving overhang on two sides. Lightly grease with cooking spray.

In a large bowl, combine flour, sugar, and salt. Add cold cubed butter and work into dry ingredients using a pastry cutter until mixture resembles coarse crumbs with pea-sized butter pieces.

Reserve 1 cup of crumb mixture for topping. Press remaining mixture firmly and evenly into prepared pan using the bottom of a measuring cup.

Bake crust for 15 minutes until just starting to turn golden around edges. Remove from oven.

While crust bakes, combine caramel bits and heavy cream in microwave-safe bowl. Heat in 30-second intervals, stirring between each, until completely smooth (about 2-3 minutes total).

Pour melted caramel over hot crust and spread evenly to edges with a spatula. Sprinkle reserved crumb mixture loosely over caramel layer.

Return pan to oven and bake for 18-22 minutes until topping is golden brown and caramel bubbles slightly around edges.

Cool completely in pan on wire rack for at least 2 hours. Use parchment overhang to lift bars out and cut into 24 squares with sharp knife.