A larding needle is a very effective, special-purpose tool.
A larding needle is used to insert small, cold strips of seasoned pork fat, called either lardons or lardoons, into a raw roast of meat, poultry, or game to provide internal basting while the roast cooks. The lardons, which melt somewhat as the temperature of the meat increases, add both flavor and tenderness to the roast.
Also known as a larder or lardoir, the larding needle is a long (anywhere from 6 to 12 inches), rather thick, stainless steel skewer with a point at one end for piercing meat. At the other end is a wooden or metal handle. The body of the needle is hollow and open along one side, so it acts as a trough. The method is to lay a lardon in the trough and push the larding needle all the way through the meat, going with the grain. If all works according to plan, the lardon will stay in the meat as you draw the needle back out. You then repeat this process every couple of inches along the length of the roast—which is just what we did in the test kitchen.
We cooked three eye of round beef roasts side-by-side, one larded using the needle, the second larded by the common method of inserting the fat into slits made on the surface of the meat with a sharp paring knife, and the third unadorned. The needle allowed us to dispense with this task much more easily and quickly than the paring knife did, and the resulting meat was more tender and flavorful because the lardons were inserted deep into the roast rather into the surface only. Not surprisingly, both larded roasts were superior to their plain counterpart.
Other versions of the larding needle are curved, while some include a clip to hold the lardon. You can find larding needles at Fante's Kitchen Wares Shop.