Ahi (fire) was started by a fire plow which consisted of two pieces of dry wood, usually hau. The larger flat stick (ʻaunaki) was held in place on the ground or mat by the feet of the fire maker who sat before it.
He held firmly in his hands a slender stick (ʻaulima) which he moved (heahiʻa, a contraction of he ahi hiʻa) by firm forward strokes over the lower one.
This plowing motion produced a groove in the lower stick and caused wood dust (hāhā) to accumulate at the forward end. In about a minute heat from the friction caused the wood to smoke and sparks to appear in the wood dust.
The lower stick was then lifted, turned over, and the sparks poured onto the fibers (pulu) of a dry coconut husk, or sometimes on kapa.
The sparks burst into flame when the kindling material was blown upon by mouth, with a bamboo blower (ʻohe-puhi-ahi), or waved vigorously in the air. The wood for cooking was lighted by fire secured in this way. (Mitchell)
Hawaiians used several means in cooking food: Baking (kālua in the imu,) Broiling (kō‘ala, kunu, pālaha, olala and pūlehu on hot coals,) Steaming (hākui and puholo with hot stones) and Broiling wrapped food (lawalu, wrapped in leaves over a fire.) (Titcomb)
Baking (kālua) was and still is done in an earth oven, or imu (old spelling is umu). The oven is prepared by digging a hole in the ground; a fire is laid and stones are placed on it to the depth of two or three stones, or enough to fill the hole.
The fire should be so laid as to burn briskly and heat the stones red hot. Embers are then removed, the stones moved to make a smooth surface.
A thick layer of banana leaves, or a layer of banana trunks, split lengthwise, is laid over the hot stones, then more leaves, banana or ti leaves and then the food to be cooked.
All kinds of foods are put into the imu together; families often shared an imu. The imu is covered with leaves after the food has been placed and then with earth to hold in the heat. (Tticomb)
When large hogs were cooked and rocks place in the cavity, the hog was wrapped in coarse kapa and mats. The hog was left until the stones had cooled, then the wrappings were removed. The cooked meat on the inside was cut away and eaten. The outer, under-done parts were cut into pieces and placed in the imu for recooking. (Mitchell)
Broiling food (kōʻala, kunu, pūlehu, pālaha, olala) using hot coals (kō‘ala) or hot ashes (pūlehu) was a common way to cook if a meal was prepared out in the fields away from home or if the small amount of food being prepared did not warrant use of an imu.
Kunu was a term almost synonymous with kōʻala, but it implied that great care had been taken in preparation. Pūlehu (heaped ashes) was cooking by shoving the food into a heap of hot ashes and embers; sweet potato, breadfruit and banana were cooked in this manner.
Pālaha (flattened out), a term used chiefly for land animals―broiling a flattened out piece of flesh. Olala was broiling by holding over the coals and turning so that all sides were heated. Dried fish did not need actual cooking, merely heating a little.
Food was cooked by being spread out flat on a level bed of coals, or it was warmed over or near a fire and periodically turned. Breadfruit and unripe bananas could be broiled this way in their skins.
Steaming in closed calabashes with tight-fitting lids (hakui, puholo) included pork, fish and fowl. These were usually heavy wooden bowls made especially for this type of cooking. The vessels were lined with ti leaves.
Flesh foods, taro leaves and perhaps other greens such as tender sweet potato leaves were added. Hot stones surrounded the food and water was added as needed to form steam.
After several hours in the closed calabash the food was tender. These “fireless cookers” were sometimes filled and carried on journeys and the food was consumed at the destination. (Mitchell)
The ki (ti) leaf was a most useful article to the Hawaiians in caring for food. The leaf is long and wide (20 in. x 6 in. is an average size,) smooth, shiny, tough, and, except for the midrib, the veins are unobtrusive.
It has no odor and is clean and fresh looking. Small foods were wrapped in a ti leaf laulau piʻao, larger in a flat bundle called laulau lāwalu.
Broiling wrapped food (lāwalu) was used a great deal. Food that had been cut into pieces, or small fish that would be lost in an imu, or burned crisp if broiled, were wrapped in leaves of the ti, occasionally in leaves of the wild ginger, which is said to have added a delicious fragrance to the fish.
The leaf bundle was toasted over the open fire, turning it occasionally and the food was cooked when the juice ceased to drip from the bundle. Mullet was “cooked with such perfection that when the banana leaves in which it had been steamed were taken off, it had received hardly a slight alteration in form and color.” (Titcomb)
The food was placed in containers to cool and was served cold. (Lots of information here is from Titcomb and Mitchell.)