Restaurants are a kind of shop present in Persona 2: Innocent Sin and Persona 2: Eternal Punishment. By paying a small amount of money, any character can buy one of the dishes or drinks served there and get a temporary stat increase. All restaurants offer another service like selling weapons or being the place where a Rumormonger hangs out.
At first, Trish won't sell ice cream. The player must first obtain a rumor about Trish selling ice creams from Demon Rumormonger Nekomata, located at the Kuzunoha Detective Agency, by donating 100,000 yen to the cat statue. Additionally, later in the story Nekomata will have another rumor available that claims she's reformed her greedy ways...sort of. The rumor has two possible randomly generated outcomes which both effect the cost of ice cream by either lowering her prices, or raising them, but adding "Lucky Ice Cream" and "North Light Vanilla" to her inventory.
Found in Kameya Alley on the Hirasaka district. It's known as "Ramen Shiraishi" in Innocent Sin and serves a variety of ramen noodles, but changes to an Izakaya-style bar in Eternal Punishment which sells Japanese snacks and sake.
The owner is referred to as the "Shiraishi Lady". Although it may not have been her true backstory, rumors in both games make her become a former secret agent that sells weapons in her store. She also has a dream of publishing an autobiography of herself which can be realized through rumors in Persona 2: Eternal Punishment. Her autobiography is littered with grandiose tales such as her having been saved by a soldier.
In order to get all the plates on the menu, the relevant rumor must be spread. Rumors must also be spread to add the Combo Plate to the menu. An extra sidequest line called "The Man Searching Quest" can be unlocked from which the Shiraishi Lady oversees.
In Eternal Punishment, the Wang Long addict here will tell you which dragon rules over you by telling her your birth month. If you tell her HASTURCOMEFORTH (in all caps) she will panic, but you will be able to pick up the Material Card "King in Yellow" on your desk at Kismet Publishing, which is required to create the Persona Hastur in the Velvet Room.
Parabellum can be found in the Aoba District commercial area.
Some time after the rumor about the Bar selling weapons and another rumor are spread, the rumor-loving Bartender moves from Narumi to Parabellum (along with all of her drinks). A rumor must be first be spread before "Front Sight" and "Rear Sight" appear on the menu. Tatsuya cannot purchase any of the drinks, as he is underage.
Ebony can be first found in the Hotel of the Narumi district. However, later in the game Narumi becomes inaccessible, obligating the Bartender, who is also a Rumormonger, to move to Parabellum (a rumor must be spread). After a certain rumor is spread, Salam will ask you to make maps of dungeons in exchange for Rare Spell Cards and Fool Tarots. Tatsuya cannot purchase any of the drinks, as he is underage.
In Eternal Punishment, due to being a minor (below 20 years old according to Japan's law) and Katsuya Suou's presence, Tatsuya Suou cannot dine anything with alcohol in it. He is the only character in the game to have this kind of restriction.