The phrase "a comfortable lunch" is correct and usable in written English.
You can use it to describe a lunch that is enjoyable and relaxing, often implying a pleasant atmosphere or setting.
Example: "We decided to have a comfortable lunch at the café, enjoying the warm weather and good company."
Alternatives: "a relaxing lunch" or "an enjoyable lunch".
Tall, rail-thin and self-assured, Ms. Freedman was in charge of one of the country's most venerable galleries, comfortable lunching with top-tier collectors like the producer David Geffen and the heiress Joan Tisch, buyers who would not blanch at the thought of plunking down a few million for a painting.
Judies also serves a variety of breakfast and lunch items in a comfortable dining area with small granite-topped tables.
But if it isn't, feel free to pick up the lunch tab with a comfortable grin and thank Tom Hamilton for the pleasure of catching up on college matters.
We ate lunch at his place — a comfortable, working-class row house — with Veronica, his girlfriend.
Vans will tour the streets on Christmas Day, removing relatives who start arguments over lunch and taking them to a comfortable pound for the night.
Employees will be more inclined to take breaks and lunch breaks when they have a comfortable space to do so.
And the three members of R.E.M. monopolized a comfortable set of upholstery in the corner, considering the lunch options.
The idea is to give a comfortable space to spend time, just reading some info about the place or having a lunch with typical foods (strawberry, peaches, mushrooms, etc).
Serving simple Italian food in a comfortable, old-world atmosphere, Forlini's is the perfect place to set aside one's legal worries over lunch.
A great lunch stop is the Angels Camp Mercantile, also on Main Street, which serves sandwiches, soups, salads and sweets in a comfortable atmosphere.
