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, green onions, grated Graviera cheese, Greek yogurt, dill, parsley, lemon zest, black pepper, and salt. Stir until all ingredients are 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 you have 3 buttered sheets stacked together.
04 - Using a sharp knife, cut the stacked filo lengthwise into 3 equal strips.
05 - Place approximately 1 tablespoon of filling near the bottom of each strip. Fold one corner diagonally over the filling to create a triangle. Continue folding the strip upward in a triangular pattern until the entire strip is used.
06 - Place each filled triangle seam side down on the prepared baking tray. Repeat the layering, cutting, and folding process with the remaining filo sheets and filling to yield 12 puffs total.
07 - Brush the tops of the assembled puffs with melted butter or egg wash for a deeper golden finish.
08 - Bake on the center rack for 20 to 25 minutes, or until the filo is crisp and deeply golden brown.
09 - Allow the puffs to cool for 5 minutes on the tray before transferring to a serving platter. Serve warm.