Place the cherries in a strainer to drain, collecting the juice in a pot.
Add sugar and cornstarch to the juice.
Heat slowly while stirring.
When it thickens, fold in the cherries.
Leave to cool.
Roll out the pie crust on a floured surface.
Cut out hearts (about 10 cm) with a cookie cutter or using a template. (I had a template made out of cardboard.)
Put the filling on one half of the hearts. (Leave edge free.)
Cut a small cross in the center of the remaining hearts, or use a mini cookie cutter to cut out a heart, for example.
Place these hearts on top of the hearts with the cherry filling and press the edges down with a fork.
Place on a baking tray with baking paper.
Brush with milk.
Sprinkle with brown sugar.
Bake in preheated oven at 200° C for about 19 to 20 minutes.