On a lightly floured surface, roll out half of the pastry and fit into a 9-inch pie plate. Trim to 1/2 inch beyond edge of pie plate for lattice top, or trim even with rim for a two-crust pie.
In mixing bowl, combine 1-1/2 to 2 cups sugar, flour, cinnamon, and salt. Add the rhubarb. Gently toss until coated. (For frozen fruit, let stand for 15 to 30 minutes or until partially thawed, but icy.)
In a small bowl, whisk together eggs and cream. Pour over fruit; toss to mix. Transfer to the pasty-lined pie plate.
On a lightly floured surface, roll out remaining dough into a 12-inch circle and cut slits for steam to escape or cut into 1/2-inch-wide strips for lattice top. Place pastry over filling and weave strips over top for lattice. Press ends of strips into crust rim and fold bottom pastry over strips. For a two-crust pie, trim top crust to 1/2 inch beyond edge of pie plate; fold extra pastry under bottom pastry and flute edge. If you like, make leaf cutouts from pastry scraps and place on pie; brush top crust with milk and sprinkle with additional sugar.
To prevent overbrowning, cover edge of pie with foil. Bake in a 375 degree F oven for 25 minutes for fresh fruit (50 minutes for frozen). Remove foil. Bake for 20 to 25 minutes more or until top is golden. Cool on wire rack. Makes 8 servings.