2 lemons
One 4- to 5-pound whole chicken
Kosher salt and freshly ground black pepper
4 sprigs fresh tarragon
3 cloves garlic
1 tablespoon unsalted butter, melted
1 1/2 cups loosely packed fresh flat-leaf parsley leaves
2 tablespoons fresh tarragon leaves
3 spring onions, dark green parts trimmed off and bulbs roughly chopped
1 small clove garlic
1/2 cup olive oil
2 tablespoons champagne vinegar
1 pinch crushed red pepper flakes
Kosher salt