This easy blueberry custard pie combines a creamy, custardy filling with ripe, juicy blueberries. The sweet filling is baked in a pie crust and you can even swap in a store-bought one if you'd like.
In a large bowl, whisk sugar, buttermilk, eggs, butter, and vanilla until well combined. Add flour and salt and whisk until no dry flour remains. Gently stir in blueberries until well incorporated.
Place pie crust in a 9-inch (23-cm) pie plate. Pour pie filling into pie crust. Bake until just set, 50 to 60 minutes.
☞ TESTER TIP: You’ll need a pie plate that can hold 5 cups of filling. You can check that your pie plate is large enough by filling your empty pie plate with water, 1 cup at a time.
Cool at room temperature for 1 hour. Refrigerate for at least 2 hours before serving.