The most dramatic difference between hand- and machine-made mayonnaise can be tasted in garlic mayonnaise made in a mortar and pestle (not the smooth chemist’s variety but one of the semi-rough marble). The texture is like velvet, the flavors are subtle, and the result is more digestible.
It was Richard Olney who showed me the best way to make aioli. Later I made the red pepper version, rouille, for Julia Child in her house at Plascassier in the south of France in 1978, when a group including the English novelist Sybille Bedford, Richard Olney, and other friends gathered and Julia let me cook. Put in the fish soup, the rouille was a sensation. Yet another version of aioli can be made by adding fresh sea urchin puree – and that result is transcendental.