Preheat oven to 375F.
Heat up oil in a large skillet over medium heat. Wring out spinach in a towel, squeezing out as much water as possible. Add spinach, onion, and salt to skillet; saute 5 minutes, stirring frequently. Add garlic, and cook for about 30 seconds. Remove from heat. Mix in oregano, dill, and nutmeg.
In a large bowl, stir together feta, ricotta, and egg until fully incorporated. Stir in the spinach mixture.
Now it’s time to make the turnovers. Take a piece of fillo dough and spread it out on a large cutting board. Spray with olive oil and put another piece of fillo over it. Spray that one with olive oil and add another layer; adding and spraying each layer until you have 3 layers. Now cut the layered fillo dough lengthwise into two, long pieces.
Put 2 1/2 tablespoons of spinach mixture at the bottom right part of each fillo strip. Fold the fillo over so the bottom comes up and meets the right side, beginning the triangle shape. Continue folding up and over until you get to the end and have a nice triangle of filled fillo. Put the triangle on a baking sheet.
One package of my fillo has 20 sheets (40 per box), so I can get 12 triangles from a package. I divide them up between 2 baking sheets.
Bake for 18-20 minutes.