Line a baking sheet with baking parchment.

Preheat the oven to 200 degrees Celsius

In a little saucepan; bring some water to boil and place the tomatoes in for a few seconds. Immediately place them in some cold water and the skinning should peal of easily. Remove the tomatoes seeds and dice the flesh. Set aside

Heat the olive oil in a frying pan and cook the red pepper and onion together for about 10 minutes, until soft. Add the tomatoes and cook for a further 5 minutes over a medium heat, until the liquid evaporates.

Allow to cool before adding the tuna, olives, hard-boiled eggs and parsley. Mix well, taste and season with salt and freshly ground black pepper.

Roll out the pastry into a large rectangle.

If you want to form them into triangles, cut them in squares. Or if you would like to achieve a half moon shape, like in the pictures, use a large pastry cutter (about 10 cm in diameter) to cut circles.

Using your finger, rub the border of each pastry with a little egg yolk, then fold over and seal by pressing down with your finger or prongs of a fork. Add a teaspoon of cold water to the remaining egg yolk and brush over the Boereks. Sprinkle with sesame seeds.

Bake for about 30 minutes until golden and crisp. Cool on a wire rack and eat at room temperature.