It comes from the engine not getting the oil hot enough: my own 'solutions' to this might not be yours, but here goes --
1. Use lighter oil for the cold weather. Once upon a time Castrol made a 10w50 version of their famous XLR (which was their 20w50 made just for this bike) that was their first "GTX" oil. Today, though, this same-label GTX oil has lots of detergents in it, so it makes the foaming worse AND causes clutch problems. So, using 20w40 oil may be the next step 'down', which I would do: here I would use the Shell Rotella Diesel-rated oil (low to no-detergent).
2. Use hotter sparkplugs, like X22ES-U or D7EA. Though only slight, this will warm the engine up a bit faster and help burn off the gas that won't burn because it is cold.
3. {I can do this, many can't...] install the Vetter Lowers on my fairing. This helps a LOT. I like 'em, too...
4. In the 1970s, in the Chicago area, some riders would block off one pipe's exhaust of each side for the cold season. The methods varied from (black painted) wood plugs to custom-made steel plug inserts. This holds the exhaust a bit longer in the exhaust ports, helping to warm the engine. It seemed to work whether they were riding the expressway or just in-town stop-and-go. I never tried it, but saw it quite often. It also helped reduce the froth in the oil tank.
I usually rode mine hard at least twice a week (which brings up the topic of gauntlet gloves...) in cold weather when I commuted to work with it (didn't have a car then, [ex-]wife was always using it) for 10 miles or more: this, plus the lighter oil, kept the froth away pretty well.
