This recipe is a modification of one from Cooks Illustrated Magazine. It is pretty close to foolproof and is easy as...pie. This makes enough for two crusts (top and bottom, or two pies that have no top crust, like Pumpkin Pie or Pecan Pie). If you only have one pie shell to make, you can freeze the other half. Just be sure it is defrosted before you try to roll it out.
The two crusts would be for a normal sized 8 or 9 inch regular depth pie. See note below for single crust deep dish pie.
Cut up the butter and lard into small pieces and put in the freezer for 10 minutes. With a food processor, process the flour, salt and sugar together. Add the butter and lard and pulse until the fat is about the size of large peas.
Mix the sour cream and ice water together until reasonably smooth. Add half to the flour/fat mixture and pulse for 3 seconds. Add the second half and pulse again.
With your fingers, pinch a bit of the mixture. If it holds together, you're done. If it is floury and dry, add 1 or 2 tablespoons more water until there is no more dry flour.
Divide the dough into two parts, forming each part into a loose disc and put each in a plastic bag in the refrigerator for at least 1/2 hour, longer is better. Or freeze for later use.
I almost always do a large deep dish pie and was always having a heck of a time rolling things out to fit, so I changed the recipe to accommodate a single large pie crust.
I just had a unique and bad experience. I bought what I thought was regular shortening and it turned out to be pre-creamed shortening. This stuff would probably be great for cookies or cake, but the texture for pie crust was all wrong. Because I didn't have enough flour to make another crust, I went ahead and used it by pressing it into the pie pan and getting the top cold enough that it held together long enough to get on the top. It baked OK, but I still prefer lard to shortening and I would definitely NOT use pre-creamed shortening. This was closer to a weird thick crumble.
However, I would also note that this bad experience still tastes great. Just an odd texture to the crust. You wouldn't want to serve it to the Queen, should she drop by. It's fine for eating.