Sauté the prepared spinach in a skillet over medium heat for 2-3 minutes until wilted and vibrant green, then drain any excess moisture and chop finely.
In a mixing bowl, combine the softened cream cheese with the minced garlic, a pinch of salt, pepper, and nutmeg, stirring until smooth and fragrant.
Add the chopped spinach and the beaten egg to the cheese mixture, folding gently until everything is evenly incorporated.
Lay out a sheet of phyllo pastry on a clean surface, keeping the remaining sheets covered with a damp towel to prevent drying out.
Brush the sheet lightly with melted butter or oil using a pastry brush, then place a spoonful of filling near one corner of the sheet.
Fold the corner over the filling to form a triangle, then continue folding in a zigzag pattern, creating a puff shape, and seal the edge with a dab of butter.
Repeat the filling and folding process with remaining sheets and filling, placing each puff on a lined baking sheet. Brush the tops lightly with butter for extra crispiness.
Bake in the preheated oven at 200°C (390°F) for 15-18 minutes, or until the puffs are golden, flaky, and fragrant with garlic and butter aroma.
Remove from the oven and let rest for 5 minutes to allow the filling to set slightly and the layers to crisp.
Optionally, sprinkle grated cheddar cheese on top immediately after baking for a melted, cheesy finish, then serve warm for the best flaky, creamy experience.
