Place stock and saffron in small pot. Bring to a boil then reduce heat to simmer and reduce the stock by half a cup to concentrate flavor, 15 minutes or so.
Place a pot of water on to boil for pasta. Once boiling, salt water and cook pasta to al dente.
Char peppers over stove burner or under broiler until skins blacken. Place in a bowl to cool and cover with plastic wrap. Once cool, peel, seed and chop.