Blueberry Rhubarb Pie
The baker and pie coach Kate McDermott has many tricks to figure out when a pie is done, but her favorite is what she calls “the heartbeat of the pie.” She listens for a sizzle that tells her that the fat in the crust is cooking the flour, and for a thumping sound that indicates that the simmering liquid is bumping up against the top crust. Also, watch for bubbling: This will tell you that the temperature is high enough that the thickeners have dissolved into the filling. All-berry pies can be too sweet and soft, so the tart crunch of rhubarb makes an ideal complement, especially in early spring. This glowing purple-magenta filling is quite spectacular.
- Serves: 1 person
- Dough for a double-crust pie, chilled (see recipe; be sure to double it)
- 2 ½cups/312 grams rhubarb, trimmed and cut into 1/2- to 1-inch lengths
- 1 ½cups/226 grams blueberries or blackberries
- ¾cup/150 grams granulated sugar, more for sprinkling
- 2tablespoons all-purpose flour
- 2tablespoons quick-cooking tapioca (also called instant, minute or small pearl tapioca)
- ⅓teaspoon salt
- Pinch of freshly grated nutmeg
- 1teaspoon fresh lemon juice
- ½tablespoon cold unsalted butter
- 1egg white, whisked with 1 tablespoon water
Step 1Heat oven to 425 degrees. Roll out both crusts. Line a deep 9-inch pie pan with the bottom crust and return both crusts to the refrigerator.
Step 2In a medium bowl, combine rhubarb, berries, sugar, flour, tapioca, salt, nutmeg and lemon juice. Toss to coat and combine, then scoop into waiting bottom crust. The fruit should come up to within 1/2-inch of the rim of the pan; do not overfill. If necessary, add more or subtract some of the fruit. Break the butter into pieces and dot over the fruit.
Step 3Lay top crust over filling. Trim excess dough from the edges and crimp, then cut 6 or 7 vents on top. Brush a light coating of egg wash over the crust, including the edges.
Step 4Bake for 20 minutes. Reduce heat to 375 degrees. Bake another 25 minutes, then open the oven and quickly sprinkle the crust with a thin coating of granulated sugar. Bake another 10 to 15 minutes, or until you see steady bubbling in the filling coming through the vents.
Step 5Remove pie from oven and listen to it: if the crust is sizzling, and the filling is audibly bubbling against the top crust, it is done. Let cool completely before serving.