The best thing is allwais to start from scratch of course but if you don't have time or if you are working in a very busy restaurant here is the perfet tecnique i promise nobody will ever find out! Most important is the quality of rice (arborio or Carnaroli)cook the chopped challots with oil add rice pour wine and a couple of cups of stock,let it dry on a hi flame until totally dry,chill on a cold table or metal baking pan on a thin layer .it will take no more than 8 minutes to cook next time you use it ,i used this tecnique in the llast 15 years it really helps a lot in a busy night ..