Beis Shammai say that flour cooked in boiling water is exempt from challah; Beis Hillel say that it is obligated. Beis Shammai say that a dough cooked by pouring boiling water over it is obligated but Beis Hillel say that it is exempt. When it comes to the cakes that accompanied a thanksgiving offering and those that were brought by a nazir, if one made them for his own use, they are exempt from challah; if he made them to sell in the market, they are obligated in challah.
If a baker made enough leaven to require challah being separated but the intention is to divide it into smaller portions for sale, it is still obligated in challah. If several women gave the baker dough to make leaven and none of them have enough individually to require challah, it is exempt.