1 1/4 pounds Yukon Gold potatoes, peeled and cut into 1-inch cubes
2 tablespoons unsalted butter
1 1/2 pounds green beans, trimmed
Chive blossoms, for garnish (optional)
In a medium bowl, combine the olive oil with the chives, parsley, mint, lemon zest, lemon juice and garlic and season with salt. Let the salsa verde stand at room temperature for 15 minutes to 1 hour.
Meanwhile, in a large saucepan, cover the potatoes with cold water, add a large pinch of salt and bring to a boil. Cook the potatoes over moderately high heat until just tender, about 8 minutes; drain and return them to the saucepan. Add 1 tablespoon of the butter and toss to coat. Season with salt.
Bring a large pot of salted water to a boil. Add the beans and cook until crisp-tender, 4 minutes; drain. Return the beans to the pot and stir in the remaining 1 tablespoon of butter. Season with salt.
Add half of the salsa verde to the potatoes and half to the beans, stirring to coat. Transfer the beans to a serving bowl. Top with the potatoes, garnish with the chive blossoms and serve right away.