Paula Deen and I have so much in common and one is that we both keep cooked potatoes around as a staple. We happened to have steak and baked potatoes the night before, so I made sure I cooked extra potatoes. Dice a baked potato, add to a hot pan with your favorite oil and cook until crispy on all sides. I used to use butter in my hash but learned from my Uncle Lanny that butter was the reason they didn't crisp up. You need oil for that! I also salt, pepper and paprika the potatoes at this time (the paprika was another secret I got from Uncle Lanny).
After the potatoes are crispy all around, or just crispy on one side if you want some softness to your potatoes, add in some diced onion and cook until the onion is as done as you like it.
Next, if I have other leftover veggies I want in my hash, I'll toss them in after the onions have cooked and before the meat. They just need a minute or two to warm up; you don't want them overcooked. Then you throw in whatever leftover meat you had for dinner the night before, diced up. The smaller you cut it, the quicker it will heat up. The longer you cook it, the tougher the meat will get, so just a minute or two will heat up diced meat. Don't be hatin' on the temperature I eat my red meat, y'all! ;o)