Mashed Potatoes and Ham Casserole

Tonight I needed to come up with a quick dinner without a trip to the store.  I had ham in the freezer & some packages of mashed potatoes to use, and I found this recipe online.  I've already lost the link but it was so easy I actually remember how to make it.  It actually turned out quite delicious.

Mashed Potatoes and Ham Casserole

4 cups mashed potatoes (I used instant potato pearls)
1 1/2 cups diced ham
1/2 onion
2 Tbsp butter (used separately)
1/4 tsp salt
1/8 tsp pepper
1/2 tsp garlic powder
1/2 cup grated cheddar cheese
1/3 cup crushed cornflakes

Dice the onion very fine (I so love my Pampered Chef chopper) and place it in a bowl with 1 Tbsp butter. Microwave the onion and butter, uncovered, for 2 minutes (stirring after one minute)
Prepare your mashed potatoes, and add the onion, ham, salt, pepper and garlic powder (you could use minced garlic instead or leave it out and I'm sure it would be fine).
Grease the bottom of a 1 1/2 quart baking dish, and pour the potato mixture into it.
Sprinkle the grated cheese on top, layer that with the crushed corn flakes, and cut up your remaining 1 Tbsp butter over the top.

Bake at 375 for 15 minutes.