Austrian Style Steak with Potato Salad

Name: Austrian-Style Steak with Potato Salad
Ingredients: 3 lb. small red new potatoes; Kosher salt, to taste; 1⁄4 cup apple cider vinegar; 1⁄4 cup pumpkin seed oil; 3 large shallots, thinly sliced; Freshly ground black pepper, to taste; Canola oil; 2 cups plus 2 tbsp. flour; 1 medium yellow onion, very thinly sliced; 1 lb. beef top round, cut into 8 equal pieces; 1⁄4 cup dijon mustard; 1 cup beef broth; 2 tbsp. cold butter, cut into small pieces; 2 tsp. balsamic vinegar; Thinly sliced flat-leaf parsley leaves