01 - Preheat oven to 375°F. Line a baking tray with parchment paper.
02 - In a mixing bowl, combine chopped artichoke hearts, spring onions, dill, parsley, grated Graviera cheese, Greek yogurt, 1 beaten egg, salt, and pepper. Mix until well incorporated.
03 - Lay one sheet of filo pastry on a clean work surface. Keep the remaining sheets covered with a damp towel to prevent drying out.
04 - Brush the filo sheet lightly with olive oil or melted butter. Place a second filo sheet on top and brush again.
05 - Using a sharp knife, cut the layered filo into 4 equal strips lengthwise.
06 - Place 1 heaping tablespoon of filling near one end of each strip. Fold the corner over to form a triangle and continue folding in a triangle pattern to the end of the strip, sealing the filling inside.
07 - Repeat the layering, cutting, and folding process with the remaining filo sheets and filling until all are used, yielding approximately 16 puffs.
08 - Arrange the puffs on the prepared baking tray. Brush the tops with the beaten egg wash for a golden finish.
09 - Bake for 20 to 25 minutes until the puffs are golden brown and crisp.
10 - Allow to cool slightly on the tray, then serve warm.