Pastry:

In a large bowl, whisk all purpose flour, granulated sugar, and kosher salt. Add the butter. With your hands, rub it into the dry ingredients until mixture resembles sand, or coarse breadcrumbs.

In a small bowl, whisk egg, water, and vanilla bean paste. Make a well in the dry ingredients. Pour the egg mixture into the well. With a bench scraper, mix until just combined, then use your hands to finish bringing the ingredients together until a soft dough forms.

Flatten into a disc. Wrap in clingfilm/plastic wrap, and refrigerate until firm, at least 1 hour, or overnight.

Blueberry Jam:

In a small saucepan, simmer blueberries and granulated sugar over medium heat until berries break down and jam thickens, about 15 minutes.

Remove from heat. Stir in lemon juice and zest. Scoop into a bowl and refrigerate until cold, at least 1 hour. Jam will continue to thicken as it cools.

Assembly:

Line a half sheet rimmed baking tray with parchment or a silicone baking mat.

On a rolling mat or lightly floured countertop, roll pastry to approximately 1/8 inch thickness. With a 4-inch round cutter, cut pastry into discs. Re-roll scraps* and cut remaining discs. You should have 12 discs total.

Arrange 6 discs on prepared tray. Spoon blueberry jam in the middle of each disc, dividing it equally between the discs and allowing a 1/2-inch border around the edge.

With a pastry brush, apply a thin strip of beaten egg yolk to the pastry border. Top with a second disc. With your fingertips, gently press the edges to seal the jam inside the pastry.

Crimp sealed edges with a fork.

With a pastry brush, brush the tops of the pastries with more of the beaten egg yolk.

With a sharp paring knife, cut a small vent in the top of each pastry.

Freeze tray 10 minutes. Meanwhile, preheat oven to 375° F (190° C).

Bake in preheated oven for 25-30 minutes, or until flaky and golden brown with blueberry jam bubbling around the edges. Transfer to a wire rack to cool completely.

Glaze:

Whisk all ingredients in a small bowl. If necessary, add more milk or confectioner’s sugar to adjust the consistency.**

Sit wire rack over a rimmed tray lined with wax paper or parchment. With a teaspoon, drizzle glaze over each pastry.

Serve immediately. Store leftover blueberry hand pies in an airtight container at room temperature for up to 2 days, or freeze for up to 3 months.