Add ground turkey, sauté for a few minutes, using a wooden spoon to break the lumps.
Add frozen vegetables, stir, season with salt and pepper; continue to simmer for 5-6 minutes.
Add tomato paste, stir and continue to simmer until the vegetables are tender. Stir in grated cheese and cook until all the liquid has evaporated. Set aside to cool.
Visually divide the puff pastry, lengthwise, into 3 equal parts. Place the prepared meat and vegetable filling in the middle part of the dough. Cut the remaining 2 parts of the dough at an angle into strips 2 cm apart. Fold the end sides of the dough, and then fold the sides as if braiding (one strip across another).
Combine yolk, milk and salt and brush the braid on all sides. Sprinkle with sesame seeds.
Bake the braid in a pan lined with parchment paper in the oven at 180°C ( 170°C fan) for 25-30 minutes or until golden in color.
Cool slightly, and serve with a salad of your choice.