Preheat oven to 400F and line two baking sheets with parchment paper. Pour the olive oil into a skillet and warm over a medium-low flame. Add in the diced onion and cook for 5-7 minutes, until translucent and the edges start to brown. Add the chopped meat and gently break it up with a fork into small pieces. Pour the minced garlic and spices into the ground beef. Cook until the meat is browned. Next, add in the frozen peas and carrots mixture. Cook for 2-3 minutes and then add the chopped parsley.
Remove the meat filling from the stove and set aside to cool slightly. Remove a puff pastry square from the packaging and set on a piece of parchment paper.
Gently brush the outer corners of the puff pastry square with the beaten egg. Add 2 tablespoon of the chopped meat to the center of the puff pastry square. Fold over the square to form a triangle. Crimp the edges of the pastry with a fork to seal it closed.
Transfer the bourekas to a parchment lined baking sheet. Repeat with the remaining bourekas. Brush the tops of the bourekas with the remaining egg wash and sprinkle with sesame seeds.
Bake until the bourekas are golden brown and crisp 22-24 minutes. Serve warm or at room temperature.
