01 - Preheat oven to 375°F (190°C). Line a baking tray with parchment paper and set aside.
02 - In a mixing bowl, combine the chopped artichoke hearts, spring onions, dill, parsley, grated Graviera cheese, Greek yogurt, 1 lightly beaten egg, salt, and pepper. Stir until all ingredients are evenly incorporated.
03 - Lay one sheet of filo pastry on a clean work surface. Keep the remaining sheets covered with a damp kitchen towel to prevent them from drying out. Brush the sheet lightly with olive oil or melted butter. Place a second sheet on top and brush again, creating a stack of 2 layered filo sheets.
04 - Using a sharp knife, cut the layered filo stack lengthwise into 4 equal strips.
05 - Place 1 heaping tablespoon of the filling near one end of each strip. Fold the corner over the filling to form a triangle, then continue folding in a triangular pattern along the length of the strip until the filling is fully enclosed.
06 - Repeat the layering, cutting, filling, and folding process with the remaining filo sheets and filling until all components are used. You should have approximately 16 filled puffs.
07 - Place the assembled puffs on the prepared baking tray. Brush the tops evenly with the beaten egg wash to promote a golden finish.
08 - Bake in the preheated oven for 20 to 25 minutes, or until the pastry is golden brown and crisp.
09 - Allow the puffs to cool slightly on the tray before serving warm.