Cut in the lard with a pastry blender or two knives until the shortening is in pea size pieces.
In a measuring cup, combine the egg and vinegar.
Add enough cold water to make one cup.
Stir the liquid into the flour mixture, adding just enough to make the dough cling together.
Stir the water in with a wooden spoon until mixed thoroughly, then gather the dough into a ball, and separate into six portions.
Cover dough and refrigerate for one hour or you can chill it covered overnight as long as you leave it at room temp for 15 minutes before rolling it.
Roll out the dough on a lightly flour surface.
Prepare the muffin pans by cutting approximately ten centimeter pie dough circles; fit the dough circles into your muffin cups and chill until ready to fill.
For the filling:
Set oven to 400°F.
Melt together butter and sugar, and cool slightly.
Beat the eggs, cream and vanilla together.
Once the sugar mixture has cooled, whisk in the egg mixture a bit at a time. Stir in the nuts.
Fill the tart shells about 2/3 full.
Bake for 15-20 minutes or till pastry is golden and filling is puffed up.
Let cool in tins for approximately 20 minutes, then transfer to a cooling rack.