I am all for any recipes that you can make ahead of the big holiday meal because who doesn’t have enough to do handling the turkey or roast and all other last minute dishes?
This recipe is very forgiving.. you can use half sweet potato and half squash flesh if you like. It is not sweet like the marshmallow-y recipes despite the half cup of sugar in it. The sugar and baking powder give it a bit of structure so it isn’t mushy.
If you don’t have buttermilk on hand you can use 1 cup of regular milk and add 1 Tbsp white vinegar to it. Let it sit 5-15 minutes and voila… buttermilk! I have used sour cream in a pinch as well.
You can bake the sweet potatoes a day or 2 ahead of time if you like. If you are baking something else leading up to the holidays just throw them in for 45-60 minutes. Mash them when they come out of the oven and then it takes no time to mix in the rest of the ingredients when you are ready to make the casserole. That makes this recipe a real cinch on the day you are serving.