Can I put the mashed potatoes on a shepherd's Pie a couple of hours in advance?

Hi Monita and Pat. No problem doing the meat portion and the taties separately or together. Both methods work fine.

I defer to Pegeen on this. Sounds like a good plan

Yes, no problem. (Monita is the best, but this is my experience making hundreds of shepherd's pies over the years.)

Just pile the mashed potatoes on to the top of the beef/lamb mixture, cover tightly with tin foil and refrigerate until ready to bake. Give it at least 30 minutes to un-chill before you put it in the oven.

For decadence, about 30 minutes before "done" time, make a few indents in the potatoes with a knife and poke small pieces of butter into the indents.

I would wait to put the mashed potatoes on until before you bake it. You can make the mashed potatoes in advance and just hold them separately