Thaw frozen spinach and squeeze handfuls to remove all the water. Put it in a medium sized mixing bowl.
Crumble the feta and add to the spinach. Mix with a fork.
In a pan, heat 2 Tablespoons of the butter until melted. Remove green ends of spring onions and chop white parts. Saute in the butter for a few minutes.
Add the butter and onion mixture to the spinach mixture along with the dill salt, pepper and the lightly beaten eggs.
Mix everything together with a fork until well combined.
Melt remaining 6 Tablespoons of butter to brush on triangles.
Carefully remove the phyllo sheets from the package. Cut into 3 inch strips. Cover the phyllo that you are not using with a piece of plastic wrap to keep it from drying out.
Brush one strip of phyllo lightly with melted butter. Place about 1 tablespoon of filling on the bottom of the phyllo strip about 1 inch from the top. Fold the bottom corner up over the filling to make a triangle. Continue folding like a flag to complete the filled triangle.
Continue until you have used all the filling.
Place triangles on a baking sheet. You may freeze them at this stage. After two hours in the freezer on the baking sheet, gently put them in a storage bag or container.
To bake them, brush each triangle with butter and bake them in a 375 degree oven for 20 minutes or until golden brown.
To bake frozen triangles, preheat oven to 325 degrees. Brush them with butter and bake prior to thawing for 35 minutes or until golden brown. Watch them closely.