Preheat the oven to 350 degrees Fahrenheit and spray a 9 x 13 x 2-inch baking dish with pan spray.

Add the ground beef to a large skillet and cook over medium-high heat until no pink remains, breaking it into pieces as it cooks. Stir in the salt and pepper.

Add the onion and bell peppers to the skillet and cook for a few minutes, until the onion is translucent and soft. Drain off the fat and turn off the heat.

Meanwhile, peel the potatoes and slice them thinly, placing the slices into a large bowl of cold water.

In a medium bowl whisk together the evaporated milk, cream of mushroom soup, and cream of chicken soup.

Drain the potatoes and pat them dry with clean paper towels before layering half of the potatoes in the bottom of the prepared baking dish.

Layer half of the meat mixture over the potatoes, then half of the sauce, followed by 1 ½ cups of the cheese. Repeat the layers using the remaining half of the potatoes, meat, sauce, and the remaining 1 ½ cups of cheese.

Top with the fried onions before covering the dish tightly with aluminum foil.

Bake for 75-80 minutes until the potatoes are tender and the internal temperature has reached 165 degrees Fahrenheit. Remove the foil and broil under high for 1-2 minutes, until golden brown on top.

Let the casserole sit for about 10 minutes before serving to allow the potatoes to soak up any residual liquid.