PRE-HEAT OVEN TO 350
DRY THE CHICKEN PIECES THOROUGHLY WITH PAPER TOWELS. SALT AND PEPPER.
BROWN CHICKEN, SKIN SIDE DOWN FIRST, IN OLIVE OIL IN A STEEP-SIDED FRYING PAN. ABOUT 5 MINUTES A SIDE.
MEANWHILE, CUT THE FENNEL BULBS CROSS-WISE INTO 1/2 INCH PIECES.
TRIM THE LEEKS, SLICE LENGTHWISE AND RINSE UNDER RUNNING WATER. DRY AND SLICE CROSS-WISE INTO 1/2 PIECES.
REMOVE THE BROWNED CHICKEN. POUR OFF ALL BUT 2 TBSPS OF FAT. LOWER THE HEAT STIR IN THE FENNEL AND LEEKS. COVER AND SWEAT FOR 2 MINUTES ON A LOW FLAME, STIRRING OCCASIONALLY.
POUR IN THE VINEGAR. RAISE THE HEAT AND ALLOW IT TO BOIL FOR 30 SECONDS. ADD THE CHICKEN STOCK. STRIP THE LEAVES FROM SEVERAL SPRIGS OF TARRAGON AND STIR IN WITH THE LIQUID.
RETURN THE CHICKEN PIECES TO THE PAN, SKIN SIDE UP. PLACE IN THE OVEN, PARTIALLY COVERED.
COOK FOR ABOUT 15 MINUTES OR UNTIL THE JUICES RUN CLEAR.
ARRANGE CHICKEN ON A WARM PLATTER AND SCATTER WITH FRESH TARRAGON OR PARSLEY.
SERVES 4