Custard pie is one of our family's favorites, and this one is especially rich and easy. It came about one Thanksgiving when I had an extra pie crust to fill in a hurry. I used to use Betty Crocker's recipe, but there just wasn't time that day, and I remembered my go-to pantry flan recipe (Spanish Flan, by user ASOTO on allrecipes.com). I threw it into the crust in a blind rush. Later, I was thrilled with the perfectly dense and creamy pie. I'll never go back to Betty Crocker again.
With just 2 cans, eggs, and vanilla, this pie filling comes together in less time than it takes the oven to preheat. A sprinkle of nutmeg is optional, but delicious!
A note about condensed milk: I skip Eagle and Lechera for the more inexpensive store brands. Surprisingly, many store brands are preservative-free, with milk and sugar the only ingredients listed. For both milks, get full-fat.
For the crust: Combine dry ingredients in a large mixing bowl, or the bowl of a stand mixer.
Grate the cold butter with a large-holed grater. Add it to the flour mixture, tossing gently to coat it. Do not rub it into the flour. The shreds should stay pretty much intact.
Combine the ice water and vinegar. With the mixer running at low speed, add some of the ice water until the dough holds together roughly, leaving lots of crumbles behind. Alternately, do this by hand.
(NOTE ON DOUGH DRYNESS: If you just hate to roll crumbly dough, you can add a bit more water at the mixing stage, until it forms more of a ball. Sometimes I add too much water. It won't ruin the crust. I just think it's a little better with less water.)
Scoop out the dough onto a floured surface, with the crumbles on top (or underneath; you do you). Roll out to about 1/4" thick or a bit thinner. Line 9" pie pan; trim edges.
For the filling: Whisk together the milks, eggs, vanilla, and nutmeg if using. Pour into crust, or strain through a fine mesh strainer for the most uniform texture.
Bake for 20-30 minutes.
To check for doneness: insert a thin knife into the custard, about halfway between the edge and the center. If there is a film of custard on the blade, give it a few more minutes. If it comes out clean, it's done!
Cool on a rack. Serve at room temperature or chilled.
Troubleshooting: if the finished custard has lots of bubbles, is weeping watery liquid, or seems curdled, it is likely overcooked. Do not insert the knife into the very center- baking until the center is fully set center risks overcooking. It will set as it cools.