Traditional Scottish Cock-a-leekie Soup - California Prunes

Ingredients

• 3 lbs bone-in (skin-on chicken legs (thighs and drumsticks))
• 3 tsp kosher salt (divided, plus more to taste)
• 1 tsp black pepper (divided, plus more to taste)
• 4 ounces thick-cut bacon (roughly chopped)
• 1 head of garlic (halved)
• 1 TBSP extra virgin olive oil
• 2 large leeks (cleaned, greens roughly chopped and whites sliced into ½-inch coins)
• 3 medium carrots (peeled and cut into ¼-inch coins–reserve the peels)
• 2 stalks celery (sliced thin–reserve any leaves or trimmings)
• 1 bunch parsley (stems and leaves separated)
• ½ cup dry white wine
• 4 sprigs fresh thyme
• 2 bay leaves
• 1 tsp whole peppercorns
• 1 TBSP unsalted butter
• ½ cup barley
• 15-20 pitted California prunes