Phyllo spinach and feta triangles are a classic Greek appetizer known as spanakopita. The phyllo dough is filled with a mixture of sautéed spinach, onions, feta cheese, and herbs, then folded into a triangle shape. The triangles are baked until the phyllo dough is golden and crispy, and the filling is warm and flavorful. These spinach and feta triangles are perfect for parties or as a delicious snack.