By nice weather I like to go to Vollspark Friedrischain and sit at the Schoenbrunn restaurant for a nice meal or drink under the sun. The waiter is extremly friendly, the setting is delightful, in the heart of the big park, the food is good, the prices not too high.
I recently tried their plate with Austrian cheese and cold cuts, it was really tasty and, even though it’s listed in the starters, can be a real meal for one person, after that I wasn’t hungry till diner. They also have a nice breakfast menu available from 10:00 to 14:00. Very hard to choose from.