Preparing beef filling:In a medium bowl, add the Kiri squares portions and press them using a spatula until the texture becomes smooth and creamy.
In a pan over medium heat. Add the olive oil, the onion, and stir for 2 minutes until it becomes soft.
Add the ground meat, salt, pepper, and stir for 10 minutes until the meat is cooked.
Remove the pan from the heat and mix the ground meat with the mixed Kiri portions.
Add the fresh mint and chopped walnuts to the ground meat mixture, mix and set aside.
Assembling the samosas:Cut the samosa dough into medium circles of 12 cm in diameter, place a full tablespoon of the beef and Kiri cheese filling mixture in the center of the dough and fold into a half moon shape with braided edges.
Place the shaped half moon samosas in an oven sheet covered with parchment paper.
In a small bowl, mix the egg yolk and white vinegar, and brush the samosas surface.
Bake the samosas in a preheated oven to 180C (365F) for 30 minutes until golden brown.