In a large skillet, heat a drizzle of olive oil over medium heat. Add chopped onion and green onion, sautéing until they become translucent, about 3-4 minutes. Stir in minced garlic and cook for an additional minute until fragrant.

Incorporate the fresh spinach into the skillet, stirring until it wilts down significantly, about 3-5 minutes. Transfer the mixture to a bowl to cool completely.

Once cooled, mix in the fresh parsley, dill, mint, feta cheese, and beaten eggs. Season the filling with salt and pepper to enhance flavors.

Preheat your oven to 375°F (190°C). Prepare your phyllo dough by laying it out on a clean surface. Layer a few sheets on top of each other and keep the remaining sheets covered with a damp towel.

For the casserole style, brush the bottom of a baking dish with melted butter. Lay down 8-10 phyllo sheets, brushing each with butter. Spread an even layer of the spinach and feta filling. Add another 8-10 layers of phyllo, buttering each sheet before tucking the edges in, scoring the top and baking for 40-50 minutes.

For rolls, brush one phyllo sheet with butter, add filling along one edge, roll into a log, and brush the outside with butter. Repeat until all the filling is used, then bake for 20-25 minutes.

For bites, cut phyllo into strips, place filling at one end of each strip, fold into triangles, brushing with butter as you go. Bake at 375°F (190°C) for 15-20 minutes.

Once out of the oven, let your spanakopita cool for a few minutes before serving.