Preheat oven to 325 degrees F.

For the crust: Combine flour and salt. Cut in shortening. Gradually add milk just until mixture will hold together. Roll and fit into 9-inch pie pan. Crimp edges.

For the filling: Boil sweet potatoes until tender. Peel and cut into 1/4-inch thick slices. Combine the sugars and spices. Layer sliced potatoes with sugar mixture in crust. Dot each layer with butter. Pour cool scalded milk over filling.

For the streusel topping: Combine all ingredients except butter. Cut butter into mixture and stir or rub until crumbly. Sprinkle on top of the filling and bake for 1 hour. Best served warm.