One of my staple cupboard ingredients is a jar or two of really good quality pasta sauce. Nothing with added sugar...just tomatoes, basil and a little cheese...or maybe roasted veggies...or spicy arrabiata...anything good and in a jar. For a quick and easy pasta sauce saute a chopped cloved of garlic with some chopped shallots until soft. Then chuck in a huge couple of handfuls of mushrooms sliced quite chunky and saute until just soft (and any water has evaporated). Finally add your jar of store bought pasta sauce and stir everything together.
I know it sounds like common sense...but it is such an easy way to jazz up a boring jar of pasta sauce. Add any veggies you like...sometiems I toss in some courgettes, eggplant...peppers...anything i have in the fridge waiting to be used up.