Preheat the oven to 375 degrees F. Line a baking sheet with parchment paper and set it aside.
Heat olive oil over medium heat in a large skillet. Add minced garlic and onion. Saute for a couple of 3-4 minutes.
Add the spinach and cook for a couple of minutes. Add in the herbs; parsley, green onion, and dill.
Add the feta, crushed red pepper, pepper, and salt. Remove the skillet from the heat and allow the stuffing to cool down.
Meanwhile, roll out the phyllo pastry; place a phyllo pastry sheet and brush it with melted butter. Add another phyllo pastry sheet over and brush again with butter. Cut it into 3 strips lengthwise.
Place about 1 tablespoon of prepared stuffing in the corner of the pastry sheet and start folding to the opposite edge and keep folding like it forms a triangle.
Place the triangles on the prepared baking sheet and bake it for 20 minutes until the pastry turns golden and crispy.
Serve the Spanakopita while it's warm.