I haven't been to Portugal yet, but I agree with smittytabb that France, Italy, and Spain are some of the best eats in Europe! I also enjoyed the food in Germany, but I couldn't eat it for the straight week whereas I haven't had that problem in the other countries. Greece, specifically Santorini, has great food and variety due to influences from other Mediterranean countries.
If you are thinking about splurging on a business class flight, Austrian Airlines' meal service is not to be missed. There is a chef who flies on board with you so he is tasting food prepared in the air and not premaking it on the ground. They also have an extensive coffee menu. My husband still considers the meal on our flight from Dulles to Vienna as one of his top 10 from our European excursions (for comparison he's been to France, Italy, Austria, Greece, and Germany).