Preheat oven to 350 degrees F.
Melt the butter and pour melted butter into your cake pans and spread with a towel to cover the pan on all sides.
Then, beat eggs in a bowl.
Now add flour, milk, salt, and baking powder.
Dice your onion.
Defrost the spinach and squeeze out ALL water with paper towels. I just left my spinach in the refrigerator overnight and it was all defrosted!
Now add spinach, onion and grated cheese to the mixture. I used my Bubbe’s grater! Bubbe uses white cheddar, but I accidentally bought yellow. Use what Jew like. Potato, potahto.
Mix that sucker up and pour into the two buttered 8-inch cake pans evenly.
Bake for 35 minutes, or until golden brown.
Cool and cut into 6 triangles per pan.
Serve warm or at room temperature.