01 - Preheat the 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, 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 on a clean work surface. Keep the remaining sheets covered with a damp kitchen towel to prevent drying. Lightly brush the sheet with melted butter. Layer a second sheet on top and brush again with butter. Repeat with a third sheet to create a stack of three buttered layers.
04 - Using a sharp knife, cut the stacked filo sheets lengthwise into three equal 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. Continue folding the strip upward in a triangular pattern, keeping the filling enclosed, until the entire strip is folded.
06 - Place each filled triangle seam-side down on the prepared baking tray. Repeat the layering, cutting, filling, and folding process with the remaining three 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 color during baking.
08 - Bake on the center rack for 20–25 minutes, or until the filo is golden brown and crisp to the touch.
09 - Allow the puffs to cool slightly on the tray for 5 minutes before serving. Best enjoyed warm.