Honeymoon Meal in Madrid

Hi! My fiance and I are going to be in Madrid on September 12 (Sunday) for just the evening. It's the last night of our honeymoon, and we're looking for a fantastic restaurant that is open on Sundays for a great meal. My fiance and I are fairly adventurous, and would probably want the meal to be around 200 euro. I saw several recommendations below, but many were closed on Sunday's/I couldn't get a feel for the price.

Any help/recommendations are greatly appreciated!

Robin