Peel and chop apples: Peel the apples and chop them into small cubes (approx. 1/2-inch size). Discard the core.
Cook Butter and Sugar: In a medium-sized saucepan, melt the butter with the sugar and bring to a boil. Once boiling, reduce heat to low and whisk in the vanilla, cinnamon, and nutmeg.
Simmer Apples: Add the chopped apples to the pot and bring the mixture back to a boil. Reduce the heat to low-medium and simmer for 10-15 minutes, stirring occasionally, until the apples are soft and fork-tender, not mushy. Reduce heat to low.
Thicken: In a small bowl, mix the cornstarch with the water until smooth. Stir this into the simmering apples during the last couple of minutes, cooking for 1-2 minutes until the sauce thickens. Remove from heat and allow the mixture to cool to room temperature.
Shortcrust Pastry
Preheat oven: Preheat oven to 356ºF (180ºC) and line a baking sheet with parchment paper, set aside.
Blend dry ingredients: In a high-speed food processor, pulse the flour and powdered sugar a few times to blend.
Add butter: Add cold butter cubes and pulse for 15 seconds until the mixture resembles coarse crumbs.
Add milk: With the processor running, drizzle in cold milk one tablespoon at a time until the dough forms a ball.
Knead lightly: Turn the dough onto a floured surface, bringing it together with light kneading. Avoid over-kneading.
Divide dough: Divide into 2 equal halves and flatten each into a round disc.
Roll out dough: Roll out one half to 4-5mm thickness (30-35cm in diameter).
Cut pastry bases: Use a 3-inch (8cm) round cookie cutter to cut out 12-14 bases. Re-roll the excess dough as needed.
Prepare tops: Roll out the second half of the dough and cut out an equal number of tops to match the bases. Set aside.
Fill Pies
Brush edges: Use a pastry brush or finger to brush the edges of each pastry base with the beaten egg.
Add filling: Place one heaped tablespoon of apple filling in the center of each pastry base.
Seal pies: Place a pastry top over each pie and use a fork to press the edges, sealing them shut.
Cut slits: Make four small slits in the top of each pie to allow steam to escape during baking.
Egg wash & Sugar: Brush each pie with the remaining beaten egg. Sprinkle with a little granulated sugar.
Bake pies: Bake for 15-20 minutes or until lightly golden. Some may appear pale, which is fine.
Cool: Cool on the baking sheet for 5 minutes before transferring to a wire rack to cool further. Enjoy warm or cool for later!
Notes
Store: Keep the mini apple pies in an airtight container at room temperature for up to 2 days, or in the refrigerator for up to 4 days.Freeze: Place the cooled pies in a single layer in a freezer-safe container or bag, making sure they are not stacked. Freeze for up to 2 months.Thaw & Reheat: To thaw, leave the pies in the refrigerator overnight, or let them sit at room temperature for a few hours before reheating. To reheat, place the pies in a preheated oven at 180°C (350°F) or an air fryer for about 5-8 minutes until warmed through and slightly crisp.