1 - To prepare the sauerkraut filling, melt the butter in a skillet over medium heat.

2 - Stir in the onion, and cook until translucent, about 5 minutes.

3 - Add the drained sauerkraut and cook for an additional 5 minutes.

4 - Season to taste with salt and pepper, then remove to a plate to cool.

5 - For the mashed potato filling, melt the butter in a skillet over medium heat.