Heat 3 tablespoons of olive oil over medium heat. Sauté chopped medium onion and green onions until translucent, about 3-4 minutes. Add minced garlic and cook for an additional minute until fragrant.

Stir in 2 pounds of fresh spinach, cooking until wilted and excess moisture evaporates. Remove from heat and let cool.

In a mixing bowl, combine the cooled spinach mixture, parsley, dill, and mint. Add crumbled feta cheese and beaten eggs. Season with salt and pepper. Mix thoroughly.

Unroll thawed phyllo dough, keeping covered with a damp towel. Preheat oven to 375°F (190°C).

For casserole style: Brush a baking dish with melted butter. Layer 8-10 sheets of phyllo, brushing each with butter. Spread spinach filling evenly, top with more phyllo sheets brushed with butter. Seal edges, score top, and bake for 40-50 minutes until golden brown and crispy.

For rolls: Take 2 sheets of phyllo, brush top with butter, place filling at one end, and roll tightly. Brush outside with butter, place on a lined baking sheet, and bake for 20-25 minutes until golden.

For bites: Cut phyllo into strips, place a small amount of filling, fold over, and brush with butter. Arrange on a lined baking sheet and bake for 15-20 minutes until crisp.