I think the secret to making a tasty shepherd's pie is to create depth of flavor at every level - otherwise you simply have some ground beef, some corn, and mashed potatoes, none of which are really that exciting on their own.
If this pile of raw ingredients doesn't inspire you, let me share how I looked at it. First the potatoes - do they terrify you?! I've gotten so many potatoes from the farm this winter and it's not surprising that without a proper cold storage area some have sprouted. It's safe to eat them if you cut away the sprouts and any green under the skin. I also found some corn in the freezer from the summer harvest and some ground beef from Snow Creek Ranch that I picked up at one of the Farmers' Markets this summer.
I love red onion - I simply diced this to add some flavor to the ground beef.
I browned the ground beef in a little extra virgin olive oil with lots of salt and pepper, then added the onions and cooked it until they softened slightly. Then I added 3 tablespoons of flour, cooked that slightly, then added some chicken stock and cooked it until it thickened.
I simmered the corn in a little heavy cream until it thickened and made flavorful mashed potatoes with a little cream, some chicken stock, some butter, and lots of salt and pepper. Then I layered everything in a casserole dish - first beef mixture, then corn, the potatoes next, and a topping of some shredded cheddar cheese. After a 40 minute bake in the oven it was heaven on a plate!