gesturesitalian
You often see this with Italians, especially when complimenting some food they just ate, but it has evolved into a more universal gesture.
Take the thumb, index, and middle finger, gather them together, bring them to your lips, and kiss them, while moving your arm away and spread your fingers, while saying MWAH!
Is there a single word for this gesture?
The Gallic shrug includes both the moue (facial gesture) along with the shoulder shrug
"Raise your shoulders; hold up your hands, palms out; stick out your lower lip; raise your eyebrows;"
This is called the blah-blah gesture.
Blah-blah. The fingers are kept straight and together, held horizontal or upwards, while the thumb points downwards. The fingers and thumb then snap together repeatedly to suggest a mouth talking. The gesture can be used to indicate that someone talks too much, gossips, is saying nothing of any consequence, or is boring.
Source: Wikipedia
If you really intend to convey you do not want to listen to what someone has to say, you can use talk to the hand, or zip your lips:
But, the more polite way is to use a shush:
You added to your question you are wanting to describe this gesture in a story. I would probably describe the hand motion as a sock puppet.
She made a mock sock puppet with her hand and silently mouthed "Shut up."
Best Answer
In English, the word used is ‘chef’s kiss’.
From Dictionary.com: