Step 1: Prep the Spinach Filling
Place the thawed spinach in a clean kitchen towel and squeeze hard to remove every single drop of excess water. (Crucial step to avoid soggy pastry!)
In a medium mixing bowl, combine the dry spinach, crumbled feta, cream cheese, minced garlic, fresh dill, beaten egg, and black pepper. Mix thoroughly until smooth.
Step 2: Prepare the Phyllo Sheets
Preheat your oven to 375°F (190°C) and line a large baking sheet with parchment paper.
Unroll the phyllo sheets on a clean surface and immediately cover them with a damp cloth to prevent cracking.
Lay 1 sheet of phyllo flat, brush it lightly with melted butter, then place a second sheet directly on top and brush again.
Step 3: Cut and Fold into Triangles
Using a sharp knife, cut the buttered sheets lengthwise into 3 equal, long strips.
Place a rounded tablespoon of the spinach filling at the bottom end of each strip.
Take one corner of the dough and fold it diagonally over the filling to form a triangle. Continue folding the triangle up the strip (like folding a flag) until you reach the end.
Step 4: Bake to Golden Perfection
Place the folded triangles on your prepared baking sheet, seam-side down.
Brush the tops generously with the remaining melted butter to ensure maximum crunch and a beautiful color.
Bake for 18 to 20 minutes in the preheated oven until the phyllo dough dishes turn deeply golden brown and ultra-crispy. Serve warm!