A London gentleman steps into a coffeehouse, orders venison, and turtle, in the instant; and (if known) a delicious bottle of port or claret: upon a clean cloth, without form, he dines at the moment of his appetite and walks away at the moment, he is satisfied.

Now, let's be clear for a moment that John Byng isn't so much describing London coffeehouses in 1798, as much as describing what non-London coffeehouses weren't. Nevertheless, his sneer is revealing of the peri-restaurant status of elite coffeehouses at the turn of the 19th century, and of the role that coffeehouses played in serving up not just food and drink, but status and culture.

But while Byng's ideal coffeehouse offers fancy variations on standard European fare and provides table service, earlier coffeehouses emphasized the exotic and didn't always resemble future restaurants. Coffee itself, obviously, had that allure. But it was accompanied by heavily spiced candies and candied food (sugarcane being also somewhat exotic). Menus also featured other drinks from far away, namely tea and hot chocolate. The "Turk's Head" was a popular name for coffeehouses, even, riffing on medieval "Saracen's Head" inns whose signs depicted just that rather than using words.

...And, of course, there were the "coffeehouses" open late, where alcoholic drinks stronger than the beer one might brew at home offered a different kind of attraction.

But an early modern or early, modern coffeehouse's menu wasn't just about what could rot your teeth. If you don't mind my borrowing from an earlier answer, I'd like to talk about the rest of the offerings, which is to say: the infancy of the coffee-shop writer cliche.

At the risk of "since the dawn of time, mankind has"-ing it, coffeehouses/cafes in the Euro-American world have "always" been linked with intellectual life. Their initial flourishing in 17C England, especially London, was by all accounts a purposeful, genteel, civilized alternative to the sprawling brawling world of taverns and liquor. Early coffeehouses (the first one in England was established in 1650) successfully marketed themselves as a place for the so-called "virtuosi or wits" (in the phrasing of contemporary writer and highly opinionated Anthony Wood) semi-elites to gather, read, and above all discuss intellectual topics. In the 1660s, Short's coffeehouse put together a library of academic and literary texts for its patrons to peruse. Other coffeehouses hosted academic lectures, discussion groups, and in one case even fencing lessons.

Coffeehouses were thus a privileged, selective alternative to raucous tavern nights (right down to the alcohol). But they were also an intellectual alternative to the world of universities. They provided a semblance of independence from patronage or oversight by state and church and older regulations. That's not to say they were sources of sedition, just that attendees were not bounded by the same limitations of instructional method that university instruction tended to follow.

And along with intellectual life, of course, they gave rise to a distinct culture or subculture surrounding them, a world of gossip and fraternizing (women are generally excluded in this era). In other words, there was a social link between coffeehouses and "that kind" of intellectual orientation as an identity. This persisted into the 18th century, and a sort of division between elite and pedestrian coffeehouses/coffeehouse cultures (no, really). While a handful of them developed reputations as centers for political or political-economic discussion along lines as specific as the maritime insurance industry, more "neighborhood"-type coffeehouses offered coffee, tea, maybe chocolate drink, newspapers, and books.

No word on pumpkin spice, though.