Wear gloves. Tear off the stems of the nettles and discard. Rinse well.
Add the olive oil and butter in a large pot.
Add chopped onions. Saute until translucent.
Add chopped garlic if you choose to and cook for an additional minute.
Add tomato paste and cook mixing for another minute, until you start smelling the tomato paste.
Add the flour and the corn flour, again cook mixing until you start smelling the flour.
Add the nettles, mix until well blended with the other ingredients.
Add the warm water and cook over first high and then medium heat.
Add the meat stok or meat boullion. Make sure these dissolve completely.
When the nettles change color and look like they are ready add salt. This soup tolerates quite a lot of salt, so taste and adjust according to your taste.
Close the heat, use a blender to reach a thick, smooth soup. It will still have some particules, if children do not like it like that, you might choose to filter it with a thin wire colander.