Prepare piecrust mix, following label directions, or make pastry from your favorite single-crust recipe. Roll out to a 12-inch round on a lightly floured pastry cloth or board; fit into a 9-inch pie plate. Trim overhang to 1/2 inch; turn under, flush with rim; flute to make a stand-up edge. Prick shell well all over with a fork.
Bake in hot oven 425º F for 12 minutes, or until golden; cool completely on a wire rack.
Beat egg yolks slightly in the top of a double boiler; stir in 1/4 cup of the sugar, salt, and milk, sprinkle gelatin over top to soften.
Cook gelatin mixture, stirring constantly, over simmering water 15 minutes, or until gelatin dissolves completely and mixture thickens slightly and coats a metal spoon.
Strain into a large bowl; stir in lemon juice and vanilla. Set bowl in a pan of ice and water to speed setting. Chill, stirring often, at room temperature just until as thick as unbeaten egg white.
While gelatin mixture chills, beat egg whites until foamy-white and double in volume in a small bowl; sprinkle in remaining 1/4 cup sugar, 1 tablespoon at a time, beating all the time until sugar dissolves and maringue stands in firm peaks. Beat cream until stiff in a bowl.
Fold meringue, then whipped cream into thickened gelatin mixture; gently fold in raspberries.
Spoon into cooled pastry shell. Chill several hours, or until firm.