San Francisco of late is cursed with sunny Sundays. After the morning mist clears, the green hills of Marin County glisten like an enchanted forest. Forget the Sunday paper, sports, brunch, everything. As if of one mind, friends all over the city are pulling on their hiking boots and tossing cheese sandwiches and apples into their backpacks. Soon a group of us is piled into someone's car and headed over the bridge for the steep wooded hiking trails of the Golden Gate National Recreation Area.

But Sundays like all good things come to an end. Here on the West Coast this grim inevitability occurs several hours later than it does on the East, but Sunday evening is a fact of life not even carefree Californians are spared. Nor are we spared the befuddlement of what to make for dinner Sunday night -- a night that is still part of the working week; unlike Friday night when you can send out for pizza or Saturday night when you go grab a bite after the movies.

Sunday night definitely signals a return to the workaday world; the world of laundry, homework, tax returns and a return to the kitchen. But this is an evening when most supermarkets perversely close early and we usualy arrive home later from our Sunday hikes.

Usually we're ravenous and usually there are friends equally ravenous that one of us cavalierly invited to dinner at some point on the trail between Stinson Beach and Mount Tamalpais.

If the slightest bit of forethought prevailed and there's a couple of pieces of leftover chicken on hand, we can concoct Golden Gate Chow Mein, a recipe I loosely adapted from that ancient sage of Western culture, Betty Crocker.

You can throw Golden Gate Chow Mein together in about half an hour -- or less if you have several chopping knives and can put everyone to work. (Someone should immediately be put on salad detail).

Unlike many chow mein recipes, this one does not call for oil or frying which is nice for the cholesterol-conscious. Golden Gate Chow Mein smacks of authenticity yet requires no esoteric Oriental ingredients and uses only fresh food; no canned stuff or monosodium glutamate. Above all it's very fast, easy, super cheap and tasty. Spoon over rice, although calorie counters may want to spoon theirs over fresh mung bean sprouts. We serve G.G. Chow Mein with brown rice, a crisp spinach and tomato salad, hot mint tea, home-baked cookies and fresh cut pineapple for dessert. GOLDEN GATE CHOW MEIN (4 servings) 1 1/2 cups uncooked white or brown rice 1 to 2 cups leftover chicken 3 stalks sliced celery 1 medium onion, chopped 1 to 1 1/2 cups chopped mushrooms 1 1/2 cups fresh mung bean sprouts 2 cups chicken or vegetable broth (or substitute chicken bouillon) 2 tablespoons soy or tamari sauce 3 tablespoons corn starch mixed with enough water to form a paste 1 cup slivered or whole almonds or cashews or peanuts

Before doing anything else, start the rice. Then in a large skillet, heat the broth or dissolve boullion cubes in water. Add chopped onion and celery and soy sauce. Poach vegetables in liquid until bright and soft. Add chicken. Stir. Combine cornstarch with water to form a paste and stir into skillet gradually. Add mushroons, bean sprouts and nuts. Cook to boiling, stirring constantly. Boil and stir one minute. Serve over rice or fresh mung sprouts.