1To make the pastry, stir together the flour and salt in a large bowl. Add the lard and butter and blend with a pastry cutter or food processor until it's blended with some pieces of fat the size of small peas.
2In a small dish or measuring cup, stir the egg and vinegar together with a fork, then add cold water to make 1/2 cup. Add to the flour mixture and stir just until the dough comes together. Divide the dough into two pieces and shape each into a disc; wrap in plastic wrap and refrigerate or freeze until needed.
3When you're ready to bake, preheat the oven to 375F.
4In a large bowl, stir together the sugar, tapioca and salt. Whisk in the cream and vanilla. Toss the peaches in the cream mixture and set aside for 15 minutes at room temperature.
5Roll out one disk of pie dough to fit a 9-inch pie plate, trimming pastry to 1/2-inch past the edge of the plate. Spoon the filling into the shell.
6Roll the remaining crust out to a 9-inch circle and lay atop the filling (cutting slits or holes for steam to escape) or cut into 1-inch wide strips and make a lattice crust. Trim the edges of the top pastry to match the bottom, and crimp the edge with your fingers or a fork. If you like, brush the top of the pie with cream, and sprinkle with sugar.
7Bake for 50-55 minutes, until golden and bubbling (if you like, place the pie on a baking sheet to catch drips). Cool to room temperature before slicing.