In my house there is no set recipe for shepherd’s pie, it’s generally a savoury mince topped with mashed potato then popped in the oven until the meat is heated through and the potato on top is browned. I don’ think I’ve ever made it the same two times running.
The meat, it can be any precooked savoury meat you wish. It can be ground, it can be cubed/diced.
Try it with chicken, beef or pork.
The mashed potato topping can be your normal potato. Sprinkle it with a little grated cheese for a change.
Maybe try it with sweet potato mashed.
Try with mashed pumpkin for something different though the top won’t brown.
If your meat is still hot, spoon into an oven proof dish then pop on some potato gems (potato jewels, tater tots, potato nuggets, frozen/pre bought) OR
Use hash browns on top, either put your oven up high or put under the griller/broiler to crisp up the tops.
Serve with your choice of veg minus the potato.
I have been known to put mashed potato onto a tray (slightly spread) and pop under a griller (or in a hot oven) to crisp and brown on it’s own. I then divided up the potato and popped on top of the savoury mince served on the plate as a faux shepherd’s pie.
I can make the meat up any time during the day ready for that night.
Make a big batch of savoury meat, use some for dinner that night and freeze the rest in portions.
I’ve also been known to make shepherd’s pie out of a meaty spaghetti bolognaise sauce.
Make individuals in a pie maker.
As far as I know there are no real rules, precooked meat with a little gravy in a dish baked with a mash on top seems to be the way it goes, the rest you make up as you go along.