Add the flour, salt, and butter to a food processor and pulse to combine until crumbly and small pieces of butter are still visible.

In a small dish, whisk the egg, water, and vinegar together and sprinkle over the flour mixture. Pulse the mixture until it begins to clump into a ball. 

Turn the pastry onto a lightly dusted work surface and gently shape into a round disc. Wrap in plastic wrap and refrigerate for 2 hours.

In a medium size dish, add the tuna, tapenade and green onions.  Whisk the egg with a fork and stir into the mixture.  Add the grated cheese and fold into the filling mixture.  

Remove the pastry from the refrigerator. On a lightly floured work surface, roll the dough to a thickness of 1/8-inch. Cut into 4-inch circles. 

Place the circles of pastry on a sheet of parchment as you cut them. Then gather the pastry scraps and lightly press into a disc, roll and cut. 

In a small dish, prepare the egg wash by whisking the egg and water together. 

Pre-heat the oven to 400°F.

Working with one pastry circle at a time, brush the edge with some of the egg wash. Pick it up in your hand as shown in the photo and add 1 tablespoons of the meat mixture inside; then pinch the pastry closed around the edges. Lay the closed empanada on the work surface and lightly press the edges together with a fork. 

Place the filled empanada on the prepared baking sheet and proceed with filling the remaining pastry circles. 

Brush the filled empanadas with egg wash and bake in the preheated oven for 10-15 minutes until golden brown.

When cool, arrange on an attractive serving plate/board with your choice of one or two dips.

Serve warm or cold along with romesco sauce and lemon dill aioli sauce for dipping.