Step 1Place the potatoes in a large saucepan and cover with water. Bring them to a boil and cook until tender, about 20 minutes. Drain the potatoes, then refrigerate overnight, covered.
Step 2The next day, quarter the potatoes, then cut them into 1/2-inch pieces. Set aside.
Step 3Heat 1 tablespoon of the bacon grease in a large skillet over medium heat and cook the onions and peppers, stirring occasionally, until the onions are soft and translucent, 20 minutes. Toss the potatoes with the remaining 3 tablespoons of bacon grease, and add the potatoes to the skillet. Cook, turning once in a while so they don't burn, until the potatoes are a nice brown color and a little crusty, 10 to 15 minutes.