TRIM THE LEEKS. CUT OFF THE ROOT AND THE DARK GREEN LEAVES. SLICE LENGTHWISE IN HALF AND RINSE AWAY ANY GRIT UNDER RUNNING WATER. PAT DRY. SLICE LENGTHWISE INTO 1/2-INCH STRIPS. DEPENDING ON THEIR LENGTH, CUT THE STRIPS CROSSWISE IN HALF.
CUT OFF THE FENNEL STALK ABOVE THE BULB AND DISCARD THE STALK. PEEL THE TOUGH OUTER LAYER OF THE BULB. SLICE LENGTHWISE IN HALF. USING A SMALL KNIFE, TRIM OUT THE TOUGH TRIANGLE AT THE ROOT END. SLICE CROSSWISE INTO 1/4-INCH HALF MOONS.
PRE-HEAT BROILER.
GRIND A HEALTHY PINCH OF SAFFRON THREADS AND A PINCH OF SEA SALT (PREFERABLY FLAKES) OR KOSHER SALT IN A MORTAR AND PESTLE. ADD 1/2 CUP OF WHITE WINE AND GRIND TOGETHER TILL THE SAFFRON DISSOLVES IN THE WINE.
MAKE A BED OF LEEKS AND FENNEL IN THE BOTTOM OF AN AU GRATIN DISH. POUR IN THE DISSOLVED SAFFRON. ADD ANOTHER 1/2 CUP OF WINE TO THE MORTAR AND PESTLE TO RINSE OUT EVERY LAST BIT OF SAFFRON AND ADD IT TO THE VEGETABLES.
DRY THE BASS THOROUGHLY WITH PAPER TOWELS.
LAY THE FILLETS SKIN SIDE UP ON TOP OF THE VEGETABLES. DRIZZLE WITH OLIVE OIL. SALT AND PEPPER. LAY A FEW SPRIGS OF THYME ON TOP OF FISH.
DEPENDING ON THE HEAT OF YOUR BROILER, COOK FOR 5 TO 8 MINUTES. THE FISH IS DONE WHEN THE BLADE OF A SMALL KNIFE INSERTED IN THE CENTER FEELS WARM WHEN TOUCHED TO YOUR BOTTOM LIP.
SERVES 4