1. In a large bowl, combine the flour and salt; Cut in the butter until crumbly–it’s easier if you cut the butter into little chunks.
2. Whisk the egg yolk into 3/4 cup of the milk, then add gradually to the flour mixture, tossing with a fork until the dough forms a ball. Add more milk, a tablespoon at a time, if necessary.
3. Divide the dough into 2 portions so that one is slightly larger than the other. Wrap each in plastic wrap and refrigerate 1 hour or until easy to handle.
4. Preheat the oven to 375 degrees F. Roll out the larger portion of dough between 2 large sheets of lightly floured waxed paper into an 18 x 13-inch rectangle.
5. Transfer to an ungreased 15 x 10 x 1 inch baking pan. Press the dough onto the bottoms of the pan and up the sides; Trim pastry to the edges of the pan.
6. In a large bowl, combine the sugar and cornstarch. Add the peaches and blueberries and toss to coat evenly. Spoon onto the pastry.
7. Roll out the remaining dough and place it over the filling. Fold the bottom pastry over the edge of the top pastry and seal edges–you can use a fork or just kind of pinch them together. Prick the top with a fork to vent.
8. Bake 45-50 minutes, or until golden brown. Cool completely in pan on wire rack.

Directions for glaze

• Combine powdered sugar, vanilla and enough milk to get a drizzle consistency. Drizzle over pie. Cut pie into squares to serve.