Blueberry Pie That Slices Cleanly

Before you start

Blueberries carry a lot of water and very little natural structure, which is why blueberry pie so often lands on the plate as a purple pool. Adding more and more starch fixes the runniness but turns the filling gummy and dull. A better approach is to cook half of the berries into a quick jam first. That drives off water and releases the fruit's own pectin, so the filling needs only a moderate amount of cornstarch and still tastes bright.

The raw berries folded in afterward keep some whole, juicy pops. A top crust with decorative cutouts or a few wide vents lets moisture escape during the long bake. As with any fruit pie, the final cue is thick bubbling in the center, and the payoff comes after several hours of cooling.

Ingredients

• Crust330 g (2⅔ cups) all-purpose flour
• 1 tsp fine salt
• 1 tbsp granulated sugar
• 170 g (¾ cup) unsalted butter — cold, cubed
• 55 g (¼ cup) vegetable shortening — cold
• 110–135 ml (7–9 tbsp) ice water
• Filling900 g (about 6 cups) blueberries — fresh or frozen, divided
• 150 g (¾ cup) granulated sugar
• 30 g (¼ cup minus 1 tsp) cornstarch
• 1 tsp finely grated lemon zest
• 1½ tbsp lemon juice
• ⅛ tsp ground cinnamon — optional
• pinch fine salt
• Finish2 tbsp heavy cream or milk
• 1 tbsp granulated sugar

Method

1. Mix the flour, salt and sugar. Cut in the butter and shortening until the mixture looks like coarse meal with some flattened butter pieces. Toss in ice water until the dough holds together when squeezed, halve it into two disks, wrap, and chill for 1 hour.
2. Put 450 g of the blueberries in the saucepan with half the sugar. Cook over medium heat, mashing, for about 8 to 10 minutes, until the mixture thickens and reduces to roughly 300 ml (1¼ cups). Remove from the heat.
3. Whisk the remaining sugar with the cornstarch, cinnamon and salt, then stir it into the hot berry mixture. Return to medium heat and stir until it boils and turns glossy, about 1 minute. Off the heat, add the lemon zest and juice and cool for 15 minutes.
4. Fold the remaining 450 g blueberries into the cooled jam. If using frozen berries, add them straight from the freezer.
5. Heat the oven to 200°C (400°F) with a baking sheet on the lowest rack. Roll one disk to 30 cm (12 in), line the pie plate, and spread in the filling.
6. Roll the second disk to 28 cm (11 in). Stamp out 8 to 12 small shapes, leaving at least 3 cm between holes, and lay the crust over the filling. Set the cutouts on top as decoration. Trim, seal and crimp the edge, brush with cream and sprinkle with sugar.
7. Bake on the hot sheet for 30 minutes. Lower the heat to 180°C (350°F) and bake 35 to 45 minutes more, until the crust is well browned and dark juice bubbles thickly through the cutouts.
8. Let the pie cool on a rack for 4 hours. The filling will look loose at first and set to a soft, sliceable jam.

Tips for success

• Wild blueberries are smaller and more intensely flavored. They give off more juice, so add 1 extra tbsp cornstarch if using them.
• Cook the jam until a spoon dragged across the pan leaves a trail that fills in slowly. That reduction does more than extra starch.
• Do not skip the lemon. Blueberries are low in acid and taste flat after baking without it.

Substitutions

Shortening

Use 225 g butter in total for an all-butter crust. It browns more and tastes richer but is a little less flaky-tender.

Cornstarch

Use 3 tbsp ground quick-cooking tapioca stirred into the raw berries. The set is clearer and slightly bouncy.

Lemon

Lime zest and juice give a sharper, more floral filling that pairs well with blueberries.

Variations

Blueberry-lemon crumb

Skip the top crust and cover the filling with streusel made from 100 g flour, 70 g sugar, 70 g melted butter and lemon zest.

Blueberry-peach

Replace 300 g of the raw berries with sliced ripe peaches and add 1 more tsp cornstarch.

Troubleshooting

Filling is soupy

The jam was not reduced enough or the pie was cut warm. Reduce the cooked berries to about 300 ml and cool the baked pie for at least 4 hours.

Filling is gluey and dull

Too much starch was used to compensate for juice. Rely on the cooked-berry reduction and keep cornstarch near 30 g.

Cutout top crust cracked between holes

The holes were too close together or the dough was too thin. Space shapes at least 3 cm apart and roll the top to 3 mm.

Storage

Keep covered at room temperature for 1 day, then refrigerate up to 4 days. The filling firms further in the fridge. Freeze whole baked pies or slices, well wrapped, for up to 3 months; thaw overnight in the refrigerator.

Safety notes

Do not taste raw dough, which contains uncooked flour. Contains wheat and milk.