Preheat the oven to 350°F (175°C). Fit the unbaked crust in a 9-inch pie plate and set the plate on a baking sheet.

Stir the caramel sauce, crushed pretzels and sweetened condensed milk together until evenly combined.

Spread the filling in the prepared crust, keeping it below the top edge.

Bake for 25 to 30 minutes, until the pastry is golden and the edges of the filling look set. The center may still wobble slightly. Cover the crust edge loosely with foil if it browns too fast.

Cool on a rack for at least 1 hour. Chill until firm for neat slices, then cut and serve.