All you need to do is throw the can into hot water, let it simmer for a minute or two, open the can, and voilà!
Heat rapidly back to the boil, then simmer gently, partially covered.
Add the butter, chicken stock, salt, bay leaf, thyme, and tarragon and bring to a simmer.
1650s, alteration of simperen "to simmer" (late 15c.), possibly imitative; not thought to be connected to simper (v.). OED says the change is "probably due to a feeling of phonetic appropriateness." Figurative sense, of feelings, "to be agitated" is from 1764. Opposite sense, in simmer down, first recorded 1871, probably from the notion of moving from a full boil to a mere simmer.
I must and will keep shady and quiet till Bret Harte simmers down a little. [Mark Twain, letter, 1871]Related: Simmered; simmering. The noun meaning "a condition of simmering" is from 1809.