Bring a medium pot of salted water to a rolling boil.

While the water is heating, wash the green beans and trim both ends.

Add the green beans to the boiling water and cook until tender, about 3 minutes.

In a large bowl, add cold water and plenty of ice to prepare an ice bath.

When the green beans are done cooking, transfer them immediately to the ice water to stop the cooking process. Drain and set aside.

In a large skillet over medium heat, melt 3 tablespoons of the butter. Add the diced onion and cook until translucent, about 5-8 minutes.

Add the remaining 3 tablespoons of butter and sliced almonds to the skillet. Cook for another 4-5 minutes, stirring frequently until the almonds are golden brown.

Add the minced garlic to the skillet and cook for an additional minute, stirring constantly.

Drain the green beans from the ice bath and add them to the skillet. Toss to coat the beans with the butter mixture and cook for about 3 minutes, or until the beans are warmed through.

Season with kosher salt and pepper. Serve immediately.