I've been fortunate to have lived in the following locations, though Florence (1 month) and Tokyo (1 week) were extended trips. Feel free to contact me for other recommendations.
Alas I only know a handful of favourites that I frequent. I make a point of visiting Borough Market when I can, arrive early to avoid crowds.
Cafe East - Vietnamese, Canada Water. The best pho I've had anywhere.
Golden Dragon - Cantonese, Leicester Square. My go-to for dim sum.
Satay House - Malaysian, Paddington. Since I don't know KL as well as I should.
Beigel Bake - Deli, Shoreditch. Spectacular salt beef bagels, opens 24 hours.
Super fun city, super reasonably-priced. Favourite locations include Club des Visionaere + Michelberger Hotel to hang out, St Oberholz + Cafe CK for coffee (former for hipster freelancers, latter for espresso), KaDeWe for the best food hall in Europe.
Transit - Modern Asian, Rosenthaler Platz. The main place I take visitors to, for Thai/Indonesian tapas-style dishes. Other location near Ostkreuz is a bit further out, but has more distinctive decor and easier to get a reservation.
Thai Ha - Vietnamese, Rosenthaler Platz. A hole-in-the-wall for a Asian guilty pleasure I can only seem to find in Germany - deep-fried duck served on a bed of vegetables with red/green/yellow curry sauce.
White Trash Fast Food - American, Schlesisches Tor. Love the BBQ beef ribs.
Burgermeister - Burgers, Schlesisches Tor. Super cute location under train tracks.
Ta'cabron Taqueria - Mexican, Schlesisches Tor.
Hasir - Turkish, Kottbusser Tor.
Cafe Valentin - Brunch, Schoenleinstrasse.
Konnopke’s Imbiss - Currywurst, Eberswalder Strasse. Friends who visit the city swear by it.
Notable mentions include Dudu (sushi), Vietnam Aroma (the best mango chicken in the city), Com Viet (Vietnamese), Hashi (Japanese/izakaya), Edelweiss (brunch), Platoon/Bite Club (street food market, more so I love the space/art hall), Castel Montecroce (pizza), and Gaston (tapas).
Favourite locations include La Palette + La Perle to hang out (especially former for sidewalk people-watching), La Grande Epicerie for the best French food hall anywhere.
Le Pre Verre - Latin Quarter. Great set menus, pleasantly surprised to find outpost in Tokyo.
Bouillon Racine - Latin Quarter. Love the duck confit, pretty Art Nouveau interior.
Au Vieux Colombier - St Germain. Floor-to-ceiling windows over lunch at this friendly bistro.
Chez Hanna - Marais. The best falafel in Paris.
Most of the recommendations here are for Florence, including Vivoli, Neri + Santa Trinita for gelato, Caffeteria del Oblate for luscious views of the Duomo from the local library cafe, Le Murate for aperitivo.
Maccheroni - In Rome, actually the only one in this list in the city.
Al Mascaron Osteria - In Venice, the most spectacular spaghetti vongole I've had in my life.
Trattoria 4 Leoni - The fiochetti di pera in salsa di taleggio e asparagi was so good I almost cried.
Trattoria Mario - The best bistecca I had in town.
Enoteca Fuori Porta - More modern take on Florentine cuisine.
Focacceria Pugi - Spectacular pizza margherita to munch on while taking in the wonderful sights.
Lupen + Margo - Lampredotto sandwiches close to San Lorenzo.
Bar Galli - Love dropping by here for breakfast.
This list is a little dated, but should still be good.
Delegates’ Dining Room - At the UN HQ. Yes, you too can dine with diplomats.
Norma's - Brunch, Midtown West.
Bubby's - Brunch, Tribeca.
Fatty Crab - Modern Malaysian, Meatpacking District.
Hill Country - BBQ, Flatiron.
Sake Bar Hagi - Japanese/izakaya, Midtown West. Love the mentaiko spaghetti.
Seoul Garden - Korean, Midtown West.
Bouley - French, Tribeca.
My favourite city outside Europe. One of the most enjoyable experiences I had there was trying out takoyaki and yakitori at the food stalls during the Gishi-Sai festival at Sengaku-ji. Very highly recommended if you're in the city in December.
Daiwa Sushi - Tsukiji. I previously described the sushi experience here as "the heights of culinary joy at Le Cordon Bleu was thought to be a one-off, until now."
Chano-Ma - Naka-Meguro. Located in a chic neigbourhood, has great set lunches and a pumpkin cake that kept me wanting more for weeks.
Honoji - Harajuku. Amazing fish set menus, with spectacular decor and city-view balcony in the Chanel building.
Miami Garden - Various locations. To check out what mentaiko spaghetti is really like.
Mae Waree at Thong Lor has the best mango sticky rice in the city, probably the country.
Taling Pling - Thai, various locations but I absolutely love the one in Thong Lor.
Baan Khanitha - Thai, various locations.
La Tana - Italian, Ekkamai. If it's one non-Thai restaurant I'd recommend, it's this one. More of a take-away with seating than restaurant. The loveliest Italian couple you'll meet in Thailand serving the most spectacular pizza and pasta. The pizza marinara comes especially recommended.
Amalfi Bistro - Italian, Thong Lor.
La Monita - Mexican, Siam. The tacos here rival the ones I had in California, located in Siam Paragon.
Toi + Kid Seafood - Seafood, Chinatown.
Gram - Brunch, Thong Lor. The best brunch in the city.
After You - Dessert cafe, various locations. The shibuya toast makes this place an institution.