Just a mile or two north of San Diego’s downtown Gaslamp District on any given weekend night, a line of eager eaters snakes out the front doors of a modest but bustling little Fifth Avenue establishment and stretches clear around the corner to the next block.

Once you’re among the select few able to squeeze into the tiny dining room, it strikes you that there’s something decidedly different about the menu offerings. Something richer and more decadent than anything else you’re accustomed to. Then, after surveying the enticing contents of a refrigerated display case near the front counter, it suddenly strikes you: There are no appetizers. There are no soups or salads. There are no entrees. Small plates, starters, side dishes, and cheese courses are all also missing.

What is there, in almost dizzying abundance, are cakes, cookies, cobblers, custards, cupcakes, croissants, pies, pastries, parfaits, puddings, tarts, trifles, mousses, éclairs, brownies, sorbets, shortbreads, scones, beignets, and ice creams. Not to mention cappuccinos, coffees, teas, lattes, and hot cocoas. As you struggle to find the common thread, to somehow muster all your powers of observation to ascertain the unifying motif at work here, you notice the sign outside the window that reads, “Extraordinary Desserts.” It’s a “eureka” moment.

The concept of the all-dessert café isn’t entirely new, but the trend is definitely catching on nationally. Not surprisingly, New York is leading the way, with five dessert restaurants as of early this year and several more on the way. But Boston’s Finale, Atlantic City’s Brûlée: The Dessert Experience, and Coco La Ti Da in Seattle are also big names on the dessert landscape.

New York’s Chikalicious opened in 2003 with 20 seats and an open sushi-bar-type counter, and the popular spot now offers a three-course menu priced at $12. Elsewhere in the Big Candy Apple, Kyotofu offers three-course desserts featuring Far Eastern flavors, such as a toasted walnut Tahitian-vanilla parfait topped with maple-soy-mascarpone mousse.

Given the business opportunity inherent in tapping into America’s sweet tooth, how is it possible that no national quick-serve player has yet emerged to corner the dessert niche? Where are our drive-thru desserteries offering not just ice cream, cinnamon buns, or doughnuts, but all of the above, plus much more? It’s a question I’ve pondered more and more recently as I visit the growing number of always-packed all-dessert establishments here in the San Francisco Bay Area.