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 - Cut the layered filo into 4 equal strips lengthwise. Place 1 heaping tablespoon of filling near one end of each strip.
05 - Fold one corner of the strip over the filling to form a triangle. Continue folding in a triangular pattern along the length of the strip, keeping the filling enclosed inside.
06 - Repeat the layering, cutting, filling, and folding process with the remaining filo sheets and filling until all 16 puffs are assembled.
07 - Place all assembled puffs on the prepared baking tray. Brush the tops generously with the remaining beaten egg for a golden egg wash finish.
08 - Bake for 20 to 25 minutes, or until the pastry is golden brown and crisp to the touch.
09 - Allow the puffs to cool slightly on the tray before serving warm as an appetizer or party snack.