For sauce (can be made up to a day in advance): Remove fillets from chicken breasts. Chop legs into 4 pieces. In a large saucepan, brown leg pieces and fillets in a little olive oil. When well-browned, deglaze with white wine (deglaze means to pour in slowly and scrape the bottom of the pan so as to dissolve the brown meat gunk in to the wine) and then cover with chicken stock. Bring to a boil, reduce heat to simmer, add parsley, thyme, garlic, and 1 tsp peppercorns. Simmer for 1 hour, then strain fat, reserving meat for other purposes (e.g., soup). Reduce broth until rich and slightly thickened; only about 1.5 c should remain.
For chicken breasts: Pound chicken breasts gently, to flatten. Crack remaining peppercorns. Coat breasts with olive oil and season with cracked pepper and salt. Grill breasts skin-side down until 2/3 done, then turn to finish. Throw a sprig of rosemary on the coals for smoke. Let stand while warming/reheating sauce, then spoon onto breasts and serve.
Jon Stewart