Preheat the oven to 350 degrees Fahrenheit.

Grate the potatoes on the smallest holes of a box grater. (You can also use a food processor to process the raw potatoes into a batter that is the consistency that you would need for potato pancakes.)

Grate a small onion on the smallest holes of a box grater as well and mix with the grated raw potatoes.

In a 10 inch cast iron skillet, cook the bacon on medium how heat until the bacon is golden and crisp. Remove the bacon from the skillet and drain on a plate lined with paper towels. Reserve some of bacon to garnish on top of the Potato Babka when it’s done cooking.

Save some of the bacon grease 1-2 Tablespoons and discard the rest. Sauté the remaining chopped onion in some of the reserved bacon grease on medium heat until it is tender and slightly golden around the edges. Set the cast iron skillet aside to be used to bake the Potato Babka in. Do not wash it.

In the large bowl that you used to grate the potatoes, add the sautéed bacon and onion, the egg, flour, 2 Tablespoons sour cream, salt, ground black pepper and mix to combine.

Use a pastry brush to distribute some of the bacon grease around the sides of the cast iron skillet, the bottom should already have enough bacon grease.

Your in the potato batter and even out on the surface. Place in the preheated oven and bake for about 45 minutes.

Brush the top of the Potato Babka with more of the reserved bacon grease, melted butter or oil. This will help to crisp up the top of it. Increase the oven temperature to 450 degrees Fahrenheit and bake the Potato Babka for another 10-15 minutes, until it is golden and crisp on the outside and cooked through on the inside.

Take the Potato Babka out of the oven, cool for 10-15 minutes and serve hot. Garnish with the reserved bacon, sliced green onions and serve with sour cream. Potato Babka is best served right away.