Spinach and feta triangles are a delicious appetizer made with phyllo dough and a filling of spinach, feta cheese, onions, and herbs. The phyllo dough is cut into triangles and filled with the spinach mixture. The triangles are then folded into a neat shape and baked until golden and crispy. Spinach and feta triangles are a great addition to any party or gathering, as they are easy to make and can be prepared ahead of time.