For the crust: (requires prep the night before)
8 tablespoons buttermilk, cold
3 tablespoons culinary lavender
2 1/2 cups all-purpose flour
2 tablespoons granulated sugar
3/4 teaspoon kosher salt
1 cup (2 sticks) unsalted butter, cold and cut into cubes
For the filling:
1 1/4 cups chopped plums
1 1/4 cups blueberries, fresh or frozen
2 teaspoons lemon juice
2 tablespoons sugar (increase if your fruit is under-ripe)
1 tablespoon corn starch
1 egg beaten with a splash of water
raw sugar, for sprinkling
- To prepare the infused buttermilk: The night before you're going to make the crust, combine the buttermilk and lavender in a small bowl, stirring to make sure the lavender is submerged. Cover and refrigerate overnight to infuse the flavor of the lavender throughout the buttermilk.
- When ready to prepare the crust: Strain the lavender out of the buttermilk and discard the buds. Combine the flour, sugar and salt in the bowl of a large food processor. Note that if you have a small food processor, you may need to make the dough in two batches. Pulse the dry ingredients to combine.
- Drop the cubed butter over the flour and pulse 10-15 times until butter is mostly chunks the size of large peas with some larger chunks still remaining.
- Add 6 tablespoons of the infused buttermilk and pulse until a dough begins to form. Test to see if the dough is moist enough but pinching a small amount between your fingers. If it holds together, then it's ready. If the dough is crumbly, add in the remaining buttermilk one tablespoon at a time until the dough holds. As a rule of thumb, too moist is better than too dry, if you're a pie crust beginner and you're unsure, add a little more buttermilk.
- Pour the dough out onto a well-floured piece of parchment paper and form into two discs. Wrap the discs in the parchment, cover with plastic and refrigerate for at least an hour, up to overnight.
- To prepare the filling: In a medium saucepan, combine the plums, blueberries,lemon juice and sugar. Cook for about 15 minutes over medium heat, stirring occasionally, until the fruit has cooked down and the juices are bubbling.
- Add the cornstarch to the bubbling fruit mixture and stir until well combined. Cook for about 2 more minutes, or until mixture begins to thicken. Remove from heat and let cool.
- To assemble: Roll out the pie dough until about 1/8-inch thick. Use a wine glass or biscuit cutter to cut out ~2.5 inch circles of dough. Spoon about 1 1/2 teaspoons of filling into the middle of each circle. Brush the edges with egg wash, place another dough circle on top and use the tongs of a fork to seal the edges. It's okay if a little bit of the filling oozes out. Repeat until all of the dough is used.
- Place assembled pies into the freezer for 30 minutes to chill. This will help them to hold their shape. While the pies are chilling, preheat the oven to 425F.
- Once chilled, remove the pies from the freezer. Brush with egg wash and poke a few holes in the top of each to let steam escape. Sprinkle with raw sugar then bake for 18-20 minutes or until golden brown and the juices are bubbling out of the top.
- Let cool on the pan for 10 minutes then transfer to a rack to finish cooling.