Slice and add onions to a pot with some butter and a pinch of salt.
Let them get a slight char on the bottom and then deglaze with water.
Repeat the process until they're nice and caramelized.
Add your garlic, fresh rosemary and thyme.
Let that toast for about a minute and then add your beef broth.
Add your pasta.
Let this come up to a simmer for about 10 minutes until that pasta's cooked through.
Add your milk, Gruyère, and cheddar.
