In a large pot bring salted water to a boil. Carefully drop, by handfuls, green beans into boiling water. Return water to a boil for 5 minutes. Immediately drain the beans and plunge them into ice water for 5 minutes. Drain and wrap in a clean cloth; set aside.
In the same pot heat butter over medium heat. Lightly brown the garlic. Remove from heat and set aside for 20 minutes.
Remove the garlic from the butter, and discard it. To the garlic flavored butter add onions and thyme. Cover the pot and braise the onion over medium heat for 5 minutes, or until soft and transparent. Increase the heat to medium-high, uncover the pot and slightly caramelize the onion.
Stir the green beans into the pot. After 1 to 2 minutes, de glaze the pot with red wine vinegar. Season to taste with sea salt, pepper and nutmeg. Sprinkle with parsley.