Roll the pie crust out until slightly bigger than the original size.

There should be this difference in size when rolled out. Poke holes into the crust with a fork. (The non-rolled crust already has holes, so you don't have to make any.)

Line up the squares of white chocolate on the crust, leaving space in between each one.

Cover with the other pie crust and use a chopstick to seal the edges.

Push down the crust tightly between the chocolates both vertically and horizontally.

It should be like this.

Use a pie cutter to cut out the pies.

They should look like this.

Pinch the edges so that the chocolate won't ooze out.

Combine the scraps, roll them out, and prick holes with a fork.

Make as much as you can.

They should look like this.

Mix just a little bit of water with egg yolk and brush onto the surface of the pies.

Bake for 15 minutes in a preheated 180-200℃ oven. Check on them halfway through.

Serve these pies with coffee or tea! You can let them cool if you'd like to have the chocolate a bit more firm, but they're also delicious when eaten piping hot.