PERHAPS the secret to the stability of the English family system is that the making of the wedding cake requires three months' prior notice. No last-minute decision if ou are to have a proper cake. And who could easily cancel the commitment that involved a pastry chief's ministrations for a quarter of a year? Finally, vows are not taken lightly when they involve eating -- particularly on a summer day -- such a dense and rich confection.

Let historians, anthropologists and astrologers tell you of the impact of Prince Charles and Lady Diana's marital vows; we will tell you of the impact of their wedding cake.

Actually, there will be eight cakes, the two major ones being baked by the Royal Marines (who, in England, are apparently very versatile) and Adams Biscuits (an enormous bakery owned by the Irish Diary Board, it has been baking royal weddin cakes for the past three weddings with a recipe from 1920). We can't tell you much about the Marines' cake (the military being used to keeping secrets). But we have actually tasted the Adams Buscuit cake, or a facsimile thereof reproduced by them -- frosting trellises, Corinthian columns, Prince of Wales feathers and all -- and whisked to New York by (even luxury has its limits) Laker Airways, followed by a three-day trip to Washington by Federal Express, then another day to get it to the actual addressee.

The cake was only one-tenth the size of the historic confection, which took 546 hours to construct with 72 eggs, 10 pounds of butter and 4 bottles of French brandy (despite this whole transatlantic promotion being sponsored by Glenlivet Scotch). But you could get the idea. Even after all those days of travel, its rock-hard sugar trellis was intact. And with the brandy providing a cloud of fumes when the package was opened, it was obvious that this cake could last forever. The cake itself -- weighty fruitcake under a thick armor of jam, marzipan and royal icing -- looked as dark and as dense as a chocolate bar, and it tasted like what should be an official standard for fruitcake: a spicy mass of raisins, currants, cherries and cake that had melded with the brandy into a nearly homogeneous mass. You could learn to love fruitcake with a cake like this. In all, this official English wedding cake tasted a long sight better, even after a transatlantic flight and a week's delay, than the typical American wedding cake tastes in its youthful prime.

Nobody sent us the the royal wedding champagne to taste, but the Bollinger company, which makes it (Bollinger Tradition R.D. 1973), isn't letting any of us miss a chance. Bottles being sold worldwide will bear commemorative labels heralding that very champagn't use (120 cases of it) for Prince Charles' wedding . They will cost around $50 a bottle, which is about what they say the royal family paid for them.

Still on tastings, but back in the everyday world, we finally got around to comparing the new French-style yogurts and found that though Yoplait and La Yogart look nearly identical, their ingredients differeing only slightly, they have substantially different personalities. Yoplait is distinctly creamer and smoother; La Yogurt tasked more of fruit, but left a slight chalky aftertaste. Agreeable as they both were, though, neither of them reminded us of Paris.

We were reminded of sumptuous buffets, however, when we tasted the new low-sodium smoked fish being prepared in North Carolina (and sold at the Low Sodium Pantry, 4901 Auburn Ave., Bethesda). While our kippered salmon and smoked trout were a little watery, as if they had been defrosted, the smoked bluefish was firm and dry. All of them had a pure smokey taste -- good products, though you have to get used to their smoked fish, which is soaked in brine before it is smoked. These fish, in providing the flavor without the salty drawback, contain about 15 to 30 mg of sodium, per ounce, about the same as fresh fish, and sell for $10 to $15 a pound, about the same as regular smoked fish (which has about 460 mg sodium per ounce). We preferred the salmon for its meaty but moist texture and delicate flavor; the bluefish was much denser and had a more pronounced fishy flavor, also quite good. Trout was no sloch either, but quite oily. Fix them up with a low-sodium bagel and low-sodium cream cheese (also available at the Low Sodium Pantry), and Sunday brunch becomes a time to foreget deprivation.