Ingredients
8 chicken thighs, bone-in, skin-on (3 1/2 to 4 pounds)
4 large cloves garlic, thinly sliced
3 large shallots, thinly sliced
3/4 cup dry vermouth
Extra-virgin olive oil
1/2 cup Dijon mustard
1/4 cup lemon juice (about 2 large lemons)
2 tablespoons fresh thyme
2 teaspoons crushed red pepper
Kosher salt
3 small leeks, root and dark green top removed
1 1/2 pounds Peewee Dutch Yellow potatoes
1 medium red onion, thinly sliced
2 tablespoons unsalted butter, plus 3 tablespoons melted butter
1 tablespoon all-purpose flour
1/2 cup chicken stock
1 1/2 cups fresh breadcrumbs, preferably from sourdough bread (see Cook's Note)
3 tablespoons chopped fresh tarragon
1 teaspoon crushed sea salt flakes
1/2 teaspoon freshly ground black pepper