3¼ cups + 2 Tablespoons all purpose flour
1½ teaspoons baking powder
3 sticks room temperature, unsalted butter (1½ cups or 12 ounces)
3 Tablespoons sugar
1½ Tablespoons sour cream
1 teaspoon good quality vanilla
In a medium bowl, stir together the flour and baking powder; set aside. In the bowl of a standing mixer fitted with the paddle attachment, combine the butter with the sugar. Add the eggs one at a time, beating just to combine. Scrape down the bowl then gradually add the dry ingredients on low speed. Scrape down the bowl again, add the sour cream and the vanilla, mixing just until the mixture comes together. Turn dough out onto a well greased half sheet pan and with flour-dusted fingers, pat the dough evenly to line the pan. Chill while preparing the filling.
Peach and Blueberry filling
The quantities are a little improvisational here. If you are using good-sized freestone peaches, about 6 or 7 should do the trick, teamed with 2 pints of blueberries. (I tend to err on the side of excess.) Gently wash the peaches. You will need to blanch the peaches in boiling water, just briefly, to soften them and make the skins easy to remove. Once you have removed the skins, (work over a bowl so you can save the juices that are dripping all over your fingers and also save the skins) halve the peaches. The pits should now be easy to remove (that’s why they’re called ‘free-stone’) and then slice each half into four or five thick wedges. Set these in a shallow bowl and give them a little squeeze of lemon or orange juice to keep them from turning color. Set them aside to cool down a bit. You don’t want to put hot peaches on a cold crust. Rinse and stem the blueberries, then lay them out on a kitchen towel to absorb the moisture.
Jessie used to cook the skins, the peach pits, and the reserved peach juices together with 2 Tablespoons of sugar and about 1/4 cup of water until the skins broke down a bit and the liquid reduced. Then she removed the pits and strained the mixture, ending up with a peach flavored sugar syrup. To the syrup she would add ¼ teaspoon of almond extract. I also like to add a little orange or lemon zest. In a separate bowl, whisk together 2 Tablespoons of finely ground tapioca, ¼ cup granulated sugar and 2 Tablespoons of brown sugar. You can add a sprinkle of cinnamon, if you like. Preheat your oven to 350 degrees.
Take your half sheet pan out of the fridge, sprinkle the tapioca/sugar mixture evenly over the chilled dough. Now place the fruit on top; you can alternate rows of peaches with rows of berries, or cover one half completely with peach slices and the other half with blueberries. When the pan is completely covered with fruit, drizzle the peach syrup over the top. It won’t cover the entire tray, but as it bakes, the juices from the fruit will bubble up and join the syrup. It takes about 40 to 45 minutes to bake. Keep an eye on things, you want the fruit to be tender, the berries to pop, as you would in a pie. Neither the crust nor the pie is overly sweet, so teaming this with ice cream and/or whipped cream is in perfectly good taste.