German Fried Potatoes and Sausage

3 pounds russet potatoes, washed and quartered
6 ounces sliced smoked bacon
1/4 cup plus 3 tablespoons apple cider vinegar
2 tablespoons German mustard
Kosher salt and freshly ground black pepper
3 tablespoons canola oil
1 medium red onion, 1/2-inch dice (about 1 cup)
4 large bratwursts or similarly sized sausages, cooked, and diced into 1/2 inch cubes
1/4 cup sliced fresh chives

Put the quartered potatoes into a pot of water over high heat.  Once boiling, boil for ~5 minutes strain out the water.  The par-boiled potatoes should be placed into the freezer for 45 min to an hour to freeze them. 

Make the vinaigrette next.
Fry the bacon in a frying pan.  Drain off 1/4 c. of bacon grease.  Blend the mustard and 3 tbsp of vinegar, then whisk in the grease to emulsify.  The result should look somewhat like thousand island dressing.  Season with salt and pepper.

Remove potatoes from freezer and cut into 1/2 inch cubes.

Pour oil and any remaining bacon grease into a large dutch oven and begin frying the onions.  Once the onions are beginning to soften, add the potatoes and season liberally with salt and pepper.  Saute the potatoes 4 to 6 min, until they are cooked through, stirring frequently.  Turn heat to med-high and continue cooking 6 to 8 min. more, until the potatoes are lightly browned and crispy.  Add the chopped sausages and bacon, and toss well with the mustard sauce.

Garnish with chives.