Arrange pie crust in pan. Peel and slice* peaches and "arrange in a concentric manner" on crust. Or you could just dump them, like I did...
Whisk sour cream, egg yolks, sugar, flour, and vanilla until just blended, and pour over the peaches.
Place the pie pan on a baking sheet if you think it might overflow. Bake for 30 minutes or until custard begins to set.
Meanwhile, make the streusel. Combine the flour and sugar, then cut in the butter using a pastry blender or fork until it resembles coarse crumbs.
After 30 minutes, sprinkle the streusel on top of pie and cook for an additional 15 minutes, or until streusel is golden and a toothpick comes out clean. Let sit at room temperature for at least an hour before serving.
Notes
*An easy way to get the skins off peaches: Bring a large pot of water to a rolling boil. Add whole peaches all at once. Boil for no more than one minute. Remove with a slotted spoon and immediately plunge them into ice water. If your peaches are ripe, the skins will just fall off.Source: my friend Wendy