Roll out the dough 1/8-inch thick on a floured surface and fit into a 9-inch pie plate. Crimp the edge decoratively and prick the bottom with a fork. Chill for 30 minutes.
Preheat oven to 425 degrees F.
Line the shell with waxed paper and fill the paper with raw rice. Bake in the lower third of the oven for 15 minutes. Remove the rice and paper carefully and brush the shell with the egg wash. Bake the shell for 15 minutes more, or until golden. Let it cool on a rack. The shell can be made 1 day ahead and stored, covered loosely, in a cool, dry place.
In a large bowl let the rhubarb macerate with 3/4 cup of the granulated sugar for 1 hour. In a saucepan combine the rhubarb mixture with the cinnamon and cloves and bring to a bowl. Simmer, stirring occasionally, until the rhubarb is almost tender. Add the strawberries and simmer, stirring, until the rhubarb is tender.
In a small bowl combine the cornstarch and the liqueur and add to the rhubarb mixture, stirring. Cook over moderately low heat until thickened. Transfer the filling to a bowl and let it cool. Chill, covered, overnight.
Preheat the oven to 350 degrees F.
In a bowl with an electric mixer beat the egg whites until foamy. Add the cream of tartar and salt and beat until the whites hold soft peaks. Beat in the remaining 1 cup granulated sugar, a little at a time, and beat until the whites hold stiff peaks. Beat in the vanilla and transfer 1/3 of the meringue to a pastry bag fitted with a decorative tip.
Spoon the filling into the shell and spread the remaining meringue over it, smoothing the top. With the tip of a small knife, score the top, forming a latticework pattern. With the pastry bag, pip meringue over the top of the pie, following the lattice design.
Sift the confectioners? sugar over the pie and bake it on a baking sheet in the middle of the oven to 10 minutes. Put the pie under a preheated broiler about 4 inches from the heat until golden.
In a bowl, blend the flour, butter, shortening, and salt until the mixture resembles meal. Add the water, tossing with a fork and adding more water if necessary to form a soft by not sticky dough. Form the dough into a ball, dust it with flour, and chill, wrapped in wax paper, for 1 hour. The dough can be made 2 days ahead and kept refrigerated, wrapped in plastic wrap. It can be frozen for 1 month, wrapped in plastic wrap and foil.
Yield: dough for 1 single-crust 9-inch pie.