Has anyone done a food-related tour they would recommend in Istanbul?
Yes I can! Culinary Backstreets Istanbul offers a series of food tours. I took one in 2016 which was called “Two Markets, Two Continents”, which started on the European side with a couple of morning food stops, then took the ferry to the Asian side and made several more food stops, including at street markets. It was pricey at $125, but lasted from about 10 am to 4:00 or 4:30 pm, there was LOTS of delicious food, and the guide was excellent. There were just 4 of us on the tour, plus the guide. At the end, I was given a small book telling about many great, small typical restaurants spread around Istanbul (with good neighborhood maps), and I have visited several on subsequent trips to Istanbul, all typical and excellent. The company offers other food tours as well. I certainly recommend them!
Though I haven't gone to their class or tours, I do often read the Culinary Backstreets blog - They are very good writers and know great places from street food to fine dining so I'd say they'd be interesting for a cooking class as well.
Both IstanbulOnFood.com and PrivateIstanbulWalkingTours.com offer great food tours. And they are both small local independent operators, rather than part of a large international tour chain.
I've been looking at Culinary Backstreets for our 2020 visit. They all look so good I don't know which one to choose!