McGee says: "Frying with Butter: Butter is sometimes used for frying and sauteing. It has the advantage that its largely saturated fats are resistant to being broken down by heat, and so don't become gummy the way unsaturated oils do. It has the disadvantage that its milk solids brown and then burn around 250F, 150 degrees below the smoke point of many vegetable oils. Adding oil to butter does not improve its heat tolerance. Clarifying does; butter free of milk solids can be heated to 400F-200C before burning."
So there's a definite disagreement there about the oil. Maybe its time for a controlled experiment or two to see who is right. The Oxford Companion to Food goes with Waitrose on this one: "This problem is lessened by mixing butter half and half with oil, or by using ghee."
McGee says 'European-style butter' is an American emulation of French butter: it's a cultured butter with a fat content higher than the standard 80%.
I don't know how far back this goes, but French chefs seem to have their own variations on the butter theme:
Steaming But What 827I bought the cheapest steamer I could find (£18 in Argos) to see if I would use it. It has been a...
"Speciality butters are made in France for professional bakers and pastry chefs. Beurre cuisinier, beurre patissier, and beurre concentre are almost pure butterfact and are made from ordinary butter by gently melting it and centrifuging the fat off of the water and milk solids. It can then be recooled as is, or slowly crystallized and separated into fractions that melt at temperatures from 27C to 40C depending on the chef's needs."
