Drop the green beans in boiling, generously salted water and cook 3 - 5 minutes, until tender but still bright green. Drain and transfer to a serving bowl.
Heat a small skillet over medium heat. Add the butter and let it melt and bubble, swirling the pan. When the butter begins to foam, turn up the heat to medium-high and cook until the butter turns amber and smells nutty — this should take just a few minutes.
Take the butter off the heat and stir in the hazelnuts and thyme. Pour the butter over the beans and sprinkle with sea salt.
Recipe by Familystyle Food at https://familystylefood.com/brown-butter-green-beans/