A dozen long-stem yellow roses for Mother's Day is certainly luxurious but definitely unimaginative. Unless those long-stem roses are made of white chocolate tinted yellow and arranged in a white wicker basket decorated with flowers painted the color of Mother's room. The imagination behind these is Carole Tauber of Rockville, who is immersed in making chocolate roses for Mother's Day next Sunday. Usually she makes baskets of chocolate soup-chickens and apples for get-well gifts, chocolate telephones and light bulbs for housewarming gifts, birthday baskets with children's names in chocolate and everything from teddy bears to diaper pins in chocolate to celebrate new babies. The chocolate can be dark or light, white, yellow, pink or green. And the shapes might be decorated with beady eyes, formed on lollipop sticks, flavored with coconut, marshmallows or cookie crumbs. This is not haute chocolate; it's "not for someone who has a discriminating palate," suggests Tauber, who explains, "I, myself, am an M & M's freak." But it can be a personalized whimsey or a grand centerpiece for an entire sweet-sixteen party. Prices range from $25 to $50; to order, call Tauber at 279-7231.

BASKETS R will cater to any mother's needs, from a salt-free diet to a craving for pickles, in its gift baskets. First the Baskets R people ask for a profile of recipient--hobbies, style, taste--then design an appropriate assortment of foods, from "gourmet" to "junk", as they put it. They wrap each item individually and include small gifts, tuck them in a handmade basket and tie it to personalized helium balloons--unless it is to be shipped out of the metropolitan area. Prices start at $25. Orders are placed by calling 385-1784.

THROUGH American and French incarnations the Galerie restaurant in Charlottesville has had one constant, its toffee shortbread, which has simply been too popular to remove from the menu. Here is its recipe, although we halved the amounts of sugar in this delicious but supersweet pastry. The recipe makes four 9-inch shortbreads, and since they are so rich we recommend squirreling three in the freezer before they are nibbled away. Be sure to cut the pieces small. TOFFEE SHORTBREAD (Makes 4 cakes) For the crust: 3 3/4 cups flour 1/4 cup sugar Dash salt 3/4 pound butter, softened For the filling: 3/4 pound butter 21 ounces sweetened condensed milk 1/2 cup sugar 2 tablespoons corn syrup Dash vanilla For the topping: 2 ounces unsweetened or semi-sweet chocolate 2 ounces butter

To make crust, combine dry ingredients. Break butter into small pieces, and incorporate into dry ingredients. To do this, work mixture with tips of thumb, forefinger and middle finger. After all the butter has been worked into dry ingredients, sift through both hands, handling the crust gently, to be sure the consistency is similar to graham cracker crumbs. Divide the batch into four 9-inch pie pans, working from the inside to the outside of the pan. Press softly, but be sure crust is set firmly. If packed too hard, the crust will burn. Place in a 350-degree oven, rotating pans every 10 minutes or so. Baking should take about 30 minutes or until crust is golden brown. Remove from oven and let cool.

To make filling, combine all filling ingredients in a saucepan. (It is very important to use a stainless steel pot; aluminum or iron will discolor filling.) Place over low heat until butter has melted completely. Then bring to a boil, and boil for 1 minute, whisking constantly to avoid burning. After boiling, remove from heat and transfer to stainless steel bowl. Let cool 5 to 10 minutes.

Divide your filling equally among the 4 baked crusts. Refrigerate immediately for 1 hour.

To top pie, melt semi-sweet chocolate and butter over low heat until creamy. Spread on top of filling, leaving 1/2- to 3/4-inch edge free. Refrigerate until the chocolate is hard.

To remove from pie pan, turn pie over, bracing the chocolate side with palm of hand. Turn right side up and serve in small wedges by cutting each round in half, then each half into 3 wedges. It freezes well.

WHO says American is in. Not Carol Cutler if you read between the titles. Her award-winning 1976 cookbook, "The Six-Minute Souffle'," has been published in paperback (Potter, $8.95) under a new French title, "Cuisine Rapide." The difference? One recipe has been deleted--a Spanish one called Dulce de Leche--and another recipe substituted--a souffle' . . . a chocolate souffle' . . . in fact, a 6-minute chocolate souffle'.

MADELEINE Kamman--cookbook author, restaurateur and cooking teacher outspoken and revered--left Boston three years ago to return to her homeland, France, and challenge Gallic professionals with a cooking school in Annecy and maybe someday, a restaurant. As of September she'll be closing the school, and as ever, she is outspoken about the reason: "The taxes required by the Socialist government in France make it virtually impossible to keep the school open." Many of her classes were filled through 1986, she reports, and she is returning the students' deposits. Instead, she will give classes and demonstrations back in the United States, complete her cookbook to be published in September 1984 and perhaps reopen her school, this time in the White Mountains of New Hampshire.

TRADITION and innovation, both will be themes at the Washington Cathedral Flower Mart May 6 from 11 a.m. to 5 p.m., at Wisconsin and Massachusetts avenues. As usual there will be the garden booths, the fruits and vegetables, the flowers themselves. And inevitably there will be the famous lobster rolls sold by the Scotland Garden Club--as well as the annual Polish kielbasa and pierogi and bake sales. This year, the innovation is a Peruvian lunch of aji de gallina--spiced chicken with walnut sauce--and alfajores, filled cookies. As every year, the crowds are expected to be dense, the music lively, the grounds grand for a picnic. For more information call 537-6200.