01 - Preheat oven to 375 °F. Line a baking sheet with parchment paper and set aside.
02 - In a mixing bowl, combine the chopped artichoke hearts, sliced green onions, grated Graviera cheese, Greek yogurt, dill, parsley, lemon zest, black pepper, and salt. Stir until all ingredients are evenly distributed.
03 - Place one filo sheet flat on a clean work surface. Cover the remaining sheets with a damp kitchen towel to keep them pliable. Lightly brush the sheet with melted butter. Place a second sheet on top and brush again with butter. Repeat with a third sheet so you have a stack of three buttered layers.
04 - Using a sharp knife, cut the stacked filo lengthwise into three equal-width strips.
05 - Place approximately 1 tablespoon of filling near the bottom edge of each strip. Fold one bottom corner diagonally over the filling to create a triangle. Continue folding the strip up in an alternating diagonal pattern, keeping a neat triangular shape until the strip is fully folded.
06 - Set each filled triangle seam-side down on the prepared baking sheet. Repeat the layering, buttering, cutting, and folding process with the remaining three filo sheets and filling to produce 12 puffs total.
07 - Brush the tops of the assembled puffs with melted butter or, for deeper browning, a light coating of beaten egg wash.
08 - Bake on the center rack for 20–25 minutes, rotating the tray halfway through, until the filo is golden brown and crisp.
09 - Remove from the oven and let the puffs rest for 5 minutes on the tray before transferring to a serving platter.