Preheat oven to 325 °F / 170°C.
Wash the spinach and squeeze the excess liquid off.
Melt the butter along with 1/4 cup of the olive oil in a large pot.
Season the chopped spinach with salt and crumple it with your hands.
Whip the eggs and ricotta into a large glass bowl.
Mix in the black pepper and the rest of the olive oil.
Stir in the spinach and keep stirring until it's well combined, then add the fresh herbs and crumbled feta cheese.
Grease a baking sheet with the oil and butter mixture.
Unroll the phyllo dough and take half of the pastry sheets. Roll the remaining pastry sheets to prevent them from drying out.
Stack five of the pastry sheets on the bottom of the baking sheet so their ends overlap its edges. Layer each sheet with some of the melted butter.
Crumple the three remaining pastry sheets, layer them on top, and brush them with melted butter.
Spread the spinach mixture on top and level it with a wooden spoon.
Unroll the remaining pastry sheets and layer them on top. Don't forget to brush each sheet with melted butter.
Tuck in the edges of the pastry sheets that stick out and brush the top of the spanakopita with melted butter.
Using a sharp knife, divide the spanakopita into 12 even-sized pieces.
Place the spanakopita in the oven and for an hour or until golden brown.
Let the spanakopita cool for at least 20 minutes.
Serve with garlic dipping sauce.