Make the dough: Mix together the flour, salt and sugar in a food processor. Add butter and pulse until it turns into a crumbly meal-like texture. Drizzle over the ice water, and pulse until the dough sticks together when squished together. Divide the dough into two disks and wrap them in plastic wrap. Place these in the refrigerator for 1 hour until firm.

Make the filling: Combine the blueberries, lemon juice, sugar and cinnamon in a bowl.

Roll the dough out on a floured surface until it is 1/8-inch thick. Using an 11 cm round cookie cutter, cut 9 circles out of the dough and press them into the bottom and sides of a muffin tin. Fill the cups with the pie filling.

Using an 8 ½ cm round cookie cutter, cut out 9 more circles and press them on top of each pie, sealing the bottom and top layers of dough tightly with your fingers.

Slice an “x” in the center of each pie, then brush the surface with the beaten egg.

Bake at 400F for 30 minutes, until golden. Cool in the pan for 10 minutes, then transfer to a cooling rack and enjoy!