Butter a 9” tart pan with a removable bottom and set aside.
Measure the flour, sugar and salt into a food processor and blend for just a few pulses to mix everything.
Add in the cubed and frozen butter and pulse to form a rough dough.
Add in the egg yolk and pulse again just until a dough barely forms.
Knead the dough as little as possible just to make it come together in a ball.
Press the dough into the bottom of the prepared tart pan, ensuring that the dough goes up the sides all the way and makes an even bottom.
Freeze for 30 minutes.
Remove the pan from the freezer and preheat the oven to 400 F.
Bake the crust for 20-25 minutes, until it is dry and golden brown.
Allow to cool on a wire rack.
Make the custard filling
In a medium sized saucepan over medium heat, whisk the milk, butter, and freshly ground nutmeg.
Bring to a low boil and turn off the heat.
In a small mixing bowl, whisk together the sugar, eggs, cornstarch, flour, and vanilla and almond extracts until smooth.
Add ¼ cup of hot milk to the egg mixture and whisk until combined well.
Slowly pour the egg mixture into the hot milk, whisking constantly until it is well combined.
Turn the heat back on to medium and allow it to start to bubble while constantly whisking.
Cook for 5 minutes while whisking constantly. It will get thicker.
Pour the custard into the prepared and cooled pastry shell.
Sprinkle the top with ground cinnamon.
Place in the fridge and chill for at least 2 hours.
Notes
This milk tart will keep well in the fridge for up to 4 days. For best results, cover the tart with a layer of plastic wrap after it has set all the way.