Can I prepare mashed potatoes 10 days in advance and freeze, then rewarm them covered, in the oven for my Thanksgiving dinner?

It’s possible, to fix the potatoes ahead of time and freeze. However, the potatoes need to be fully cooked, and I usually add a little concentrated lemon juice or white wine vinegar to the water to help keep from oxidizing. You’ll also need to get all the air out of the bag and refrigerate to cool first, then freeze. I’ve had best results just doing the mashed and spices by themselves and warming in the microwave, then mixing in the heated milk, cream or butter just before serving. The milk can sour or curdle if added and then frozen.

All Things Mashed Potatoes HERE