I am no good in the kitchen really, but an aunt of mine tried to impart some cooking tips to me once.
She would cook the sweet potatoes (normally with butter, sugar and cinnamon) and once cooked, she would mash it up and then freeze it in portions.
The portions she would use in stews. To add flavor and also to thicken a stew (hmmm, I don’t know if you use the word stew… ) Anyway… I have tried this and it works well. Especially since my kids frown upon almost everything that resembles a vegetable. So since they like stew, I add the mashed sweet potato to the stew and they munch away with happy faces :-)
Then I also know that she freezes the sweet potato for normal reheating and eating… but I don’t know how she did that.
Anyway – I hope the comment helps a bit.