1. Preheat oven to 350 degrees Fahrenheit. Grease a baking dish with two tablespoons butter.
2. Bring a large pot of water to a boil. Add potatoes and boil until fork-tender, about 20 minutes. Strain. When cool enough to handle, slice potatoes into 1/4-inch rounds and season with salt, pepper, and paprika.
3. Melt remaining two tablespoons butter in a sauté pan over medium heat. Add onions and sauté until translucent, about seven minutes.
4. Layer potatoes, eggs, cheese, and onions in prepared baking dish. Continue to layer until baking dish is full. Top with sour cream. Bake for 40 minutes, or until top is golden. Rakott krumpli does not freeze well but will keep in the refrigerator for up to four days.