IT must be spring. Restaurants are popping up like jonquils and are offering as wide a range of tastes as spring flowers do colors. Latest in the University City Loop is Cafe Natasha, which is one of the best bargains to be found in recent years - a three-course dinner, including an elegant entree, is $10.50.

The small, neat restaurant, which seats about 40, is owned by Behshid Bahrami and his wife, Hamishe, who formerly operated the Little Kitchen in the Paul Brown Building downtown. He cooks, she bakes and takes care of the dining room, and both are experts. They serve, according to the menu, "definitive cuisine with a Persian flair," and they do it with style. Service is good, and the personnel is happy to explain the Persian dishes.

Persia now is Iran, but Bahrami's work is different from, say, Saleem's, which also deals in Iranian meals from a site a few blocks east. There is less garlic, more meat marinated and grilled in "shishleek," or "shashlik" or "shish kebab" style. The dish is basically the same, with only the language different. Shashlik, for example, is Russian, and the meals at Natasha show a slightly more Russian influence, as northern Iran borders on the southern part of what used to be the Union of Soviet Socialist Republics.

Much of the time, thankfully, dinner knows no international boundaries.

The menu at Natasha is small - entrees include three styles of beef, one superlative lamb and one chicken, all grilled, plus baked codfish and a vegetarian meal. Pita bread, delicious Persian tea, Bulgarian feta cheese and some spicy greens of the season (fresh cilantro, parsley, green onions and radishes) arrive as the first course, and the second is either a more traditional salad or a tangy, delicious lentil soup known as "osh."

Another pleasant note about Natasha is the presence of ground sumac (or sumakh) on the table in a shaker and looking exactly like paprika. Sumac is a little different, it's a "barberry," dried and ground, and it has a slightly astringent, piquant flavor, not as hot as pepper but with a faint sharpness. It is used primarily on grilled meat, and is tasty, but also can be sprinkled on pita bread or yogurt.

Speaking of yogurt, it's available as one of some additional appetizers that include dill-and-cucumber yogurt and some fascinating Persian pickles that are similar to chutney but not so hot. They have a sweet-sour tang, and I found them a delightful flavor. The yogurt, served for dipping, is amazing, arriving thick as whipped cream and with a lovely sour quality, and guaranteed low-calorie by the menu.

Some olive oil is served alongside, and I didn't believe the combination could be that good - even though it certainly obeys Pollack's Food-and-Wine Law, that two great dishes always make a great combination, and that a great food and a great wine are a perfect complement, no matter what the experts say.

All entrees are accompanied by either white basmati rice or herbed rice, and the Natasha rice is wonderful, with its own rich flavor and beautiful, individual kernels that come out as individual as snowflakes.

The lamb at Natasha was superlative, perhaps the best lamb I've ever eaten in a St. Louis restaurant. Marinated and well-rubbed with spices, including hints of cumin and cilantro, the loin-cut lamb was tender and delicious, with all the rich flavor that well-prepared lamb can bring. Chicken was almost as good, arriving in juicy and extremely tasty chunks, the edges grilled nicely. The baked fish, sprinkled with flavored breadcrumbs, was cooked to the exact moment, with all its mild, lovely flavor coming through. The vegetarian plate includes "kookoo," a Persian souffle, much like a quiche, made with herbs, eggs and nuts; and a dish of stewed eggplant, chick peas, garlic, onion and mint. The platter also includes rice and the cucumber-yogurt side dish.

A couple of pies and a cheesecake or two are the dessert choices, and Hamishe Bahrami has a splendid touch with crust. Apple pie was outstanding - and very American - with a rich, buttery crust and apples of the perfect shade of tenderness. Peach custard with nuts was tasty, but not quite up to the apple.

Cafe Natasha hopes to have an alcohol license and a wine list in the next few months, but for the time being, patrons can bring their own. A light red, perhaps a Beaujolais or even a Pinot Noir, goes best with the meat dishes.

The U. City Loop has grown into the finest ethnic-dining area in the city, and Cafe Natashsa is one more jewel in an already heavy crown.