BaÂ·sidÂ·iÂ·oÂ·myÂ·coÂ·ta. A phylum of fungi characterized by a spore-bearing organ, the basidium, that is usually a clavate cell that bears basidiospores after karyogamy and meiosis. Some mycologists have raised the class Basidiomycetes to the phylum or division level.
Add the onions to the skillet and increase the heat to medium-high. Cook until they begin to turn dark brown and somewhat soft, about 5 minutes. Add the oil and a pinch of the fine sea salt; continue cooking until the onions are soft and caramelized, about 5 minutes longer.. Soft, dark brown onions in five minutes. That is a lie. Fully caramelized onions in five minutes more.
Make the caramelized onions: Melt the butter and 1 teaspoon of olive oil in a large saute pan over medium-high heat. Add the onions and sprinkle with 1 tablespoon brown sugar, about 1 teaspoon Kosher salt and several good grinds of fresh pepper. Cover for 10 minutes. Remove the cover and stir the onions.