Place the slices of dough next to each other and allow to thaw. Clean and wash spring onions and cut into fine rings. Wash and chop the thyme. Cut roast beef into fine strips. Mix with spring onions and thyme.
Season with salt and pepper.
Cut the dough slices diagonally in half. Spread the roast beef mixture with a teaspoon on one side of each of the 8 dough triangles. Fold over the other side and press down the edges. Whisk the egg yolk and 2 tsp. water.
Coat the surface of the triangles with it.
Place on a baking tray lined with baking paper. Bake in a hot oven (electric cooker: 225 °C/circulating air: 200 °C/gas: level 4) for 10-15 minutes until golden brown.
Wash, quarter and seed the tomatoes. Finely dice tomatoes and mozzarella. Wash basil, cut leaves into fine strips. Mix vinegar, salt, pepper and 1 pinch of sugar. Embezzle oil.
Mix with tomatoes, mozzarella and basil. Arrange salad and roast beef pockets.