Sari's Finnish spinach pancakes

My kids call them alien pancakes due the green colour...
They are Yummmmm and you got to love it when the kids are learning life lesson too...
Pancakes/Letut recipe:
6dl milk
2 eggs
3dl plain flour
2 tbsp sugar
1 tsp salt
50g melted butter
Method of making:
Whisk milk, eggs and melted butter.
Add dry ingredients and whisk.
Let sit for 20 minutes to let flour "swell".
Cook on hot pan with cooking spray/butter both sides.
Best eaten whilst warm.
For spinach ones add chopped up fresh/frozen spinach.