if you want a really simple sauce for pasta - it's ds1's favourite and he's been making it for himself since he was about 8.
Cook the pasta according to the packet (and cooking a double portion and saving one in the fridge for the next day is a good idea - easy to heat up in the microwave or a pan of boiling water for a couple of minutes)
In the bowl you're going to have your pasta from, pour a good slurp of double cream (enough to cover all your pasta easily), a few splashes of lemon juice (I keep a bottle of Jif lemon in the fridge and just use a few splashes from it), a squirt of garlic puree from a tube or a clove or two of crushed fresh garlic and a couple of spoonfuls of pesto to taste.
Mix the whole lot together and zap in the microwave for a minute. See if it needs a little longer (usually takes somewhere between a minute and two minutes depending on how much I'm making).
Stir in pasta and you're ready to go.
It's tasty and simple and has a bit more protein in that normal pasta pesto. It's also very easy to adapt - there are lots of different pestos out there or use something like hummus or peanut butter or gentleman's relish or other chopped herbs or a spoon of curry paste etc. Change the lemon juice for sweet chilli sauce or sherry or orange or vodka and so on. Use coconut water or coconut cream or ricotta or marscapone instead of cream. Garlic can be left out or you can use things like ketchup, tomato paste, sun dried tomato paste, grated cheese, crumbled cheese (for things like blue cheese or feta), anything tasty that you like really.
Then you can add stuff in - for ease add more protein by buying a thick slice of ham/chicken/beef/smoked salmon/whatever you like from the deli counter and chopping into mouth size bits, adding to the sauce before or after cooking.
Little cherry tomatoes cut in half and added in work well. Anything you can eat raw you can chop up and throw into the sauce before or after cooking and not need to worry about it being properly cooked. Nuts and raisins can be good with lots of flavour combinations.
Things like peas or other veg that need to be cooked in boiling water for more than a minute can be added to the pasta at the appropriate time so they cook to be ready when it's time to drain the pasta.
Then just mix the whole lot together... usually works out well.
If she gets bored with pasta, the sauces work well with rice too for a cheat's risotto - cook rice (use a packet if want it really easily or quickly) and then stir the sauce through. Yes it would make an italian mama throw her hands up in horror if she thought that you were trying to pass it off as proper risotto... but as something quick and easy and tasty and on the table in a few minutes flat, it's great!