Heat up a cast iron skillet on medium low flame and quickly saute the pepper and onions together until nice little char marks start to form, a few minutes. Transfer them to a bowl and mix with the sliced spinach and set aside until ready to use.
Sprinkle some flour on a board board or kitchen counter and place the dough on top. Sprinkle more flour on top and using the palm of your hand gently press the dough down to form a circle.