- 5 tablespoons butter, divided
- 2 large onions, chopped
- 4 cloves garlic. chopped
- Salt and pepper
- 2 pounds Idaho or Russet potatoes, peeled and cubed
- 1/3-1/2 cup buttermilk
- 2 tablespoons fresh dill, chopped
- Salt and pepper
- 1 loaf Italian or peasant-style white bread
- 3/4 pound Gruyère cheese or Comté cheese
- 2 pounds kielbasa sausage
- 1 large bunch fresh radishes
- Flat leaf parsley and chives, chopped
- 4 large deli pickles, garlic or half-sour
- 3/4 cup brown mustard or grainy Dijon mustard
- 3 tablespoons sour cream
In a medium skillet over medium heat, melt 3 tablespoons butter. Add the onions and garlic, then season with salt and pepper and cook to light caramel in color, 20-25 minutes.
Meanwhile, cover the potatoes with water and bring to a boil. Salt the water and cook the potatoes until tender; drain and return to the hot pot to dry the potatoes off a bit. Mash the potatoes with the buttermilk, caramelized onions and dill. Season with salt and pepper, to taste.
Shred the cheese on the large side of a box grater.
Heat a griddle pan over medium-high heat. Cut 6-inch lengths of sausage and butterfly them open. Griddle the sausages for a few minutes on each side to crisp and brown.
Lightly toast four slices of Italian bread on both sides on a baking sheet under a hot broiler.
Heat a small skillet over medium to medium-high heat. Wash and quarter the radishes. Melt the remaining 2 tablespoons of butter in the pan; when the foam subsides, add the radishes and season with salt. Toss for 2-3 minutes; remove from the heat and toss with a small handful of chopped chives and parsley.
Halve the pickles.
Spread and mound about 1 inch of potatoes on the toasted bread. Top with the cheese and place in the lower third of the oven under the hot broiler. Cook to bubbly and lightly brown.
Combine the mustard and sour cream.
Top the pierogi-wiches with kielbasa and drizzle with the sour cream-mustard sauce. Serve with the radishes and a pickle alongside.