A GASTRONOMIC visit to Toronto these days can be an exciting experience. Canada's city-on-the-lake has become one of the best and most sophisticated food towns on the North American continent. Not only does it have superb restaurants and excellent hotels, but also hundreds of small, ethnic, family food shops and tiny husband-and-wife restaurants integrated with open-air markets representing dozens of cuisines from around the world.

The city fathers publicly reject the melting pot idea of mixing everybody up so that separate cultures gradually disappear. Instead, they opt for the checkerboard concept of separate neighborhoods. The results are stunning. I have tasted my way across town, from little shop to little shop, from an Indian Samosa meat-filled pastry to Russian black bread with toasted onion chips and Polish kielbasa sausage.

Another interesting point about Toronto is that its hotel dining rooms seem to compete on equal terms with its restaurants. Some of the finest cooking, for example, is in the dining rooms of the charming, small and unusual Windsor Arms Hotel. Only four stories high, with vine-covered walls, it looks more like an English country inn than a modern hotel in an industrial city. Part of the hotel's success is due to its owner, George Minden, an accomplished gastronome and afficionado of wine who works closely with his imaginative and inventive Swiss-born executive chef, Herbert Sonzogni.

Of the hotel's four dining rooms, the most complicated and largest is the Courtyard Cafe. The hotel is U-shaped and it originally had an open courtyard in the center. About five years ago, Minden decided to spend more than $1 million to cover it with a glass roof to make a multi-level, single room to seat more than 150 persons. It is now an impressive, gardenlike space with hanging greenery, potted plants and trees growing everywhere.

The atmosphere is distinctly Parisian -- a subtle combination of a brasserie, cafe and Montparnasse student hangout.

Throughout this long day there is one specialty on the menu that is called for more often than any other "chicken liver pate Windsor."

Somehow, Sonzogni has succeeded in balancing the simplicity of the chicken livers with exactly the right aromatic spices -- nothing too bland, nothing too strong.

If you have a food processor and an electric beater, you can put it all together at almost lightning speed. If you have to grind and beat by hand, it will take longer, but you can still do the job pretty well.

At refrigerator temperatures, this pate slices neatly. But let it come to room temperature and it will spread with perfect ease on French bread, toast or crackers. Pickles and any form of chutney go well with it. HERBERT SONZOGNI'S CHICKEN LIVER PATE WINDSOR (Makes 2 quarts) 2 tablespoons top-grade olive oil 2 tablespoons whole black peppercorns 2 cloves garlic, peeled and halved 1/3 cup chopped green scallions 1/4 cup shallots, peeled and sliced 1 bay leaf 1 1/2 pounds chicken livers 1 1/2 pounds white pork back fat, unsalted, chunked 1 1/2 tablespoons salt 1 1/2 ounces cognac, or armagnac, or good California brandy 1 1/2 ounces Madeira semi-dry Enough 1/8-inch-thick slices, either white pork fat back or fat bacon, to line the terrine pan and cover the pate during baking.

The trick that makes this pate so memorable is that you begin by giving a lightly burnt taste to the aromatic spices and vegetables. For perfect results, this has to be dead right, neither too strong nor too weak.

Set the frying pan on high heat. Lubricate its bottom with the olive oil. When the oil is very hot, almost at the point of smoking, but not quite, dump in, all at once, the peppercorns. Stir them around steadily until they explode. At once remove the pan from the heat, turn off the heat and, as quickly as possible, dump into the very hot oil the garlic halves, the scallions, the shallots, and the bayleaf. Stir them all around so thay they burn slighltly, then leave it all in the frying pan, uncovered, to cool.

Now, to deal with the chicken livers: Put the whole livers into a large mixing bowl and add the contents of the now-cooled frying pan. Working gently with a wooden spoon, mix everything together. Now transfer the liver mix -- batch by batch, according to the size of your work bowl -- to your food processor and run the motor until all the bits are finely chopped and the livers are churned into a perfectly smooth puree. In my food processor, it takes 5 to 7 seconds. Do not overdo the churning or the livers will become a sticky paste. When they are all done, transfer them back to the mixing bowl, cover them and hold them cool in the coldest part of the refrigerator.

Assembling the pate:

Put the white fat -- batch by batch, if necessary -- into the work bowl of the food processor and run the motor until the fat, too, is a smooth puree. Transfer it to the bowl of an electric beater and whip it, at high speed, until it is absolutely smooth and almost fluffy. At once turn down the beater to slow speed.

Now begin feeding into the fat, large spoonful by large spoonful, the liver mixture. When it is all in and thoroughly mixed, with the beater still running, sprinkle the salt and the cognac and madeira. When the mixing is complete, turn off the beater and return the pate mixture, again covered, to the refrigerator. o

Baking in a water bath:

Preheat your oven to 225 degrees. Line the bottom and sides of your terrine pan with the slices of fat or bacon. Have the side slices hanging over the edge of the pan by a couple of inches or so, to enable them to be folded over the top of the pate when it is in the pan. Carefully spoon in the pate mixture, smoothing it down slightly, but making sure that you do not disturb any of the lining strips. When all the pate is in, fold over the hanging strips and put on the lid.

Adjust the oven shelf so that the terrine pan will be exactly at the center.

On the shelf place a larger pan filled to a depth of about 3 inches with boiling water -- what French cooks call a bain marie. Stand the loaded terrine pan in this hot water. Leave it to bake, almost entirely unsupervised, for 5 hours. Just top up the bath with more boiling water about once every hour.

When the baking is done, take the pate pan out of its water bath and let it cool slowly to room temperature. Then chill it overnight in the refrigerator.

Next day, if you want to unmold it, dip the terrine pan into a basin of hot water just long enough for the metal to warm through and ever so slightly loosen the lining strips. Then, remove the visible lining strips from the top of the pate, overturn the pan onto a serving platter, and shake out the pate. Peel off the remaining lining strips and decorate the pate in any way that pleases you.