One afternoon in July, executives at Unilever’s corporate headquarters in Englewood Cliffs, N.J., had decided it was the right time to serve up, of all things, Thanksgiving dinner. Inside the test kitchen next to a conference room, about half a dozen women in aprons and tie-back hats hurried about a long table, laying out the victuals they’d cooked especially for the occasion. The feel was festive, right down to the pine cone-and-pumpkin centerpieces on the tabletop-but the purpose was pure business. Everything on the menu was made, to a greater or lesser degree, with mayonnaise. Hellmann’s mayonnaise.