01 - Preheat oven to 375°F. Line a baking tray with parchment paper and set aside.
02 - In a mixing bowl, combine the chopped artichoke hearts, green onions, grated Graviera cheese, Greek yogurt, dill, parsley, lemon zest, black pepper, and salt. Stir until evenly incorporated.
03 - Lay one filo sheet flat on a clean work surface. Cover the remaining sheets with a damp towel to keep them from drying out. Lightly brush the sheet with melted butter. Place a second sheet on top and brush again with butter. Repeat until 3 sheets are stacked and buttered.
04 - Using a sharp knife, slice the stacked filo lengthwise into 3 equal-width strips.
05 - Place approximately 1 tablespoon of filling near the bottom of each strip. Fold one corner diagonally over the filling to form a triangle, then continue folding the strip upward while maintaining the triangular shape.
06 - Place each filled triangle seam side down on the prepared baking tray. Repeat the layering, cutting, filling, and folding process with the remaining filo sheets and filling to yield 12 puffs total.
07 - Brush the tops of the assembled puffs with additional melted butter or egg wash for a deeper golden finish.
08 - Bake for 20 to 25 minutes, or until the filo is golden brown and crisp throughout.
09 - Allow the puffs to cool slightly on the tray before serving warm.