Prepare the Crust:

1. Preheat your oven to 425°F (220°C).
2. Roll out your pie dough to fit your pie plate, with a slight overhang.
3. Transfer the dough to the pie plate, trim the edges, and crimp as desired.

Prepare the Filling:

1. Peel the peaches and slice them about ½ inch thick.
2. Arrange the peach slices in the pie crust, starting from the outside and working your way toward the center.
3. In a medium bowl, whisk together the Greek yogurt, egg yolks, sugar, flour, and vanilla until smooth.
4. Pour this custard mixture evenly over the peaches.

First Bake:

1. Bake the pie for 30 minutes, or until the custard is just beginning to set.
2. While the pie is baking, prepare the streusel topping.

Make the Streusel:

1. In a medium bowl, cut the cold butter into the flour using a pastry cutter or your fingertips until the mixture resembles coarse crumbs.
2. Stir in the sugar until well combined.

Finish Baking:

1. After the initial 30 minutes of baking, remove the pie from the oven.
2. Sprinkle the streusel mixture evenly over the center of the pie (consider using a pie shield to protect the crust edges from burning).
3. Return to the oven and bake for an additional 15 minutes, or until a knife inserted into the center comes out clean.
4. Cool the pie on a wire rack for at least one hour before serving.

Serve:

Enjoy warm with a dollop of freshly whipped cream (unsweetened) or a scoop of vanilla ice cream.