RESTAURANT REVIEW : Decor--Not the Menu--Is the Star Here : An uneven production by the kitchen staff of Tuscany can put a damper on an elegant dining experience.

When the Santa Barbara executives wanted to sequester themselves for an uptown kind of meal, they headed south, leaving their gleaming white stretch limo outside the tall doors of Tuscany.

On the same recent Monday night, when certain among the Thousand Oaks locals, fashionably casual in linen and fine leather shoes, decided to take a late meal of grilled vegetables and risotto, they came here, to the fashionable and elegant Tuscany.

It’s easy to see the seduction. Tuscany has enjoyed a sterling reputation as that rare restaurant serving authentic regional cuisine in a sophisticated, even posh, space--all seen after by an aggressively solicitous staff.

Make no mistake, the place is a knockout.

White tablecloth and candlelight. Gleaming black Deco-era chairs. Cool pastel walls--the exception an opulent salmon-colored, glassed-in room--set off by the random free-standing Roman column here, the 9-foot-tall tropical tree there, the original art everywhere, and the mirrors, mirrors, mirrors lending happy conceit to a sleek bar whose foot-rest area has its own glass-block lighting system. Upon entering, you just know that the menu, if it looks half as studied as this, will have everything you could possibly want.

It does. Only not, sadly, in the manner in which you may want it.

Tuscany of late has food problems. So many of the dishes here, meticulously configured on the plate for breathtaking presentation, fall down in taste, in texture, in their very execution.

At its worst, Tuscany will serve up a precious soft-shell crab whose saute oil has a hard, burnt edge; whose stuffing near the carapace is ominously metallic; whose inherent delicacy is overwhelmed by its heavy-handed treatment.

While you might not order such a special, you will join all other diners in trying the complimentary bruscetta, which arrives before the menus and is a tired, graying tomato-garlic slush prepared long in advance of its heaping upon toast that lasts but a minute before soaking right through. This is no way to win culinary friends, no way to help the diner accept that a $100 tab for two will be worth it.

But then, just as suddenly, Tuscany will show that, at its best, it can still summon and serve up a piece of king salmon expertly cooked within a firm potato pancake and spectacularly sauced in garlic cream. Or that it can dependably deliver on a simple rustic plate of pasta with garlic, oil, parsley and chili peppers. And in all cases do it with style, beautiful arrangement on the plate, and waiters who are as convivial and receptive as any on Piazza Navona.

What to make of all this? A disquieting confusion over Tuscany’s two faces: one bespeaking an exceptional ethos, the other showing randomness from the kitchen. You’ll have to think carefully about whether it’s worth the money. Tuscany, meanwhile, may wish to think about whether it is in the entertainment or restaurant business first.

The best appetizer sampled features shrimp, marinated in lemon and herbs, grilled and served around mixed greens and accompanied by a piece of sweet goat cheese ($10.50). The result was bracing; plump, perfectly cooked, richly flavored shrimp foiled by a light but pungent salad arrangement. Grilled polenta with mushrooms and gorgonzola ($8) represents a terrific combination, as well, the cornmeal pieces complementing the woodsy mushrooms and pungent cheese.

But avoid a special of portobello mushroom ($8), in which three measly thin strips of pre-grilled, cold, black-charred mushroom cap arrive alongside the standard “nest” salad accompanying so many of the appetizers, the shrimp among them. Likewise avoid the Caesar salad ($6.25), of the weak-kneed Easy Listening variety, heavy on Parmesan cream and robbed of the punch of sufficient garlic and anchovy and sweetened further by paprika croutons.

Pleasant but unexceptional are grilled marinated summer vegetables accompanying the greens and goat cheese ($7.50). A mere four--count them, four--slices of cold, pre-grilled squashes and eggplant were satisfying, if less than memorable, and certainly less than enough to kick a real appetite into gear.

Pastas proved vexing, the delightful garlic-and-oil preparation ($10.75) notwithstanding (minor flaw even here, though: the menu promised spaghetti, the dish arrived with thinner spaghettini). A dish of penne alla puttanesca ($11.50) was--no euphemisms will soften things here--simply disastrous. What should be a vivid, red-pepper-edged lusty tomato sauce, redolent of garlic and earthy black olives and spiked with capers, was more tired mush in which no particular flavors could be differentiated. Worse, the noodles were overcooked.

A vegetable risotto ($14.50) shored things up in the starch department but suffered, in the end, from runniness, the mark of rushed cooking.

The salmon in potato crust ($18.50) is clearly a Tuscany home run. And a veal piccatta ($18), in which extra-thin medallions are properly flash-sauteed, were set apart by a delightfully fragrant lemon sauce--a cut above the standard lemon-and-caper treatment.

Loin of lamb ($22), a special one night, was perfectly handled: roasted rare, sliced, and fanned out attractively atop a patty of dense risotto adrift in a moat of intensely flavorful port wine-and-golden-raisin sauce. That the dish was so hot upon arrival that the sauce continued to bubble and the meat continue to cook was a mild, albeit critical, distraction.

But breast of pheasant ($18), similarly sauced, lacked flavor in the meat and, as dining progressed, imparted an unpleasant greasiness on the plate.

Tuscany’s wine list is extensive, well-chosen, and fairly priced. An exceptional bottle of Chardonnay, the ’91 Morgan from Monterey County, presents an abundant, floral perfume and near-viscous weight for $23, making it the perfect complement for the salmon or veal. House wines by the glass--an uncharacteristically astringent Merlot ($4.50), an OK but everyday Chianti ($4)--are juggish by comparison and fall well below the pretension of the menu.

Desserts were mixed. Best was creme brulee ($6), on one night delightfully firm, flame-glazed and orange-scented (though on another night candyish as pudding and studded with mushed-out raspberries). Lemon cake ($5) was gorgeous, alluring, nice in the cake but done in, ultimately, by heavy frosting--an out of balance act not unlike Tuscany itself.

* WHERE AND WHEN

Tuscany Il Ristorante, 968 S. Westlake Blvd., Thousand Oaks, 495-2768. Lunch from 11:30 a.m. to 2 p.m. Monday through Friday; dinner from 5:30 to 10 p.m. Monday through Saturday (closed Sunday). Major credit cards. Dinner for two, without wine or tip, from $45 to $75.