Tuna cooked in tomato sauce is a favorite. But after the third reincarnation, it does tend to get a tad bit old.
For this version, I freshened it up a bit with cherry tomatoes and lots of basil.
Heat up olive oil in a pan, drop the cherry tomatoes to soften them, and squash them to release the juice. Better yet, cut them into two - pressing on them might release a shot of wayward hot tomato sauce. Add leftover sauce, and a handful of chopped fresh basil. In the absence of leftover sauce, a packet of Del Monte spaghetti sauce will do in a pinch - the flavors are already balanced and does not need much tweaking. I also added a generous splash of white wine.
It helps if you have basil ready for harvesting in the garden. The parent plant has self-sown already, and these are the second generation plants.
Again, I always have a container of cooked spaghetti noodles - I make sure there are plenty of leftovers, separate from the sauce, so I can make the exact dish that I want for that day, be it plain pesto, Aglio y Olio, or red sauce.
Drop the noodles, cover to heat it all up and blend the flavors - and serve. Definitely does not taste like leftovers.
*** Note: No pasta? no problem. This is just as good served over hot rice.