Gaza's rich clay deposits were the likely reason for the favored cooking method, said el-Haddad, 35, who is from Columbia, Maryland.
Another local specialty is tiny stuffed squid with dill, spices, raisins and rice.
Gaza's border blockade has restricted many imports, raising the price of fuel and basic ingredients, such as sesame paste tahini, olive oil, meat and spices.
For years, smugglers defied the blockade by hauling in goods through tunnels linking Gaza to Egypt. Israel has progressively loosened the blockade; what remains are long power cuts and a ban on most exports, choking Gaza industry and keeping unemployment and poverty high.
Urban sprawl has eradicated most of Gaza's farmlands. Israel limits access to farms near the border because militants have used the areas to fire rockets. Israel also restricts where fisherman can cast their nets, driving up the price of seafood.
Gazans are experts at recycling.
Qishta, the Rafah housewife, built her kiln from clay dumped by smugglers as they dug tunnels under the nearby border with Egypt. With her husband unemployed for years, she relies on U.N. food packages.
Rawan Salmi, a busy 39-year-old school teacher and mother of two, can no longer cook ahead for an entire week and freeze portions since daily power cuts mean food will spoil quickly. Instead, she cooks a day at a time.
El-Haddad and Schmitt, of Miami, visited Gaza in 2010 to research their book. They found Palestinians eager to show off their dishes and passionately arguing over the tastiest way to prepare meals like okra and lentil stew.
Transforming meals into recipes was another challenge. Through re-testing and pleas to women to repeat instructions, the authors said they recorded generations of oral knowledge.
Some dishes that proved nearly impossible to find, like the roasted watermelon salad, because the authors came in the wrong season.