Begin by preparing the nettle. Pour about 4 1/5 cups (1 L) of lightly salted water in a pot and leave it on the stove to come to a boil. Clean and wash the nettle thoroughly under running water, then add it to the boiling water. Stir and boil about 10 min.
In another container, strain the water from the nettle and save it (don't throw it out, it contains all that good iron for your blood) for the porridge. Wash the nettle again under running water, squeeze it gently and cut it.
Heat the oil in a pan and fry the finely chopped onion and garlic in it until softened. Add the flour by sprinkling it in (to prevent floury lumps from forming) and braise until golden.
Add the paprika, stir and immediately (to prevent the paprika from burning) pour in the nettle water in a thin trickle, while stirring nonstop. If needed, salt and sprinkle with black pepper. Boil the porridge to the desired consistency.
My grandma used to make it a little runnier, she would stick a piece of bread on her fork and scoop from the porridge.