Chicken Schnitzel Sandwich with Horseradish Cream and Radicchio

Ingredients

• 1 cup sour cream
• 3 tbsp. fresh grated horseradish
• 2 tsp. cider vinegar
• 1 head radicchio, cored and halved, leaves separated
• Kosher salt and freshly ground black pepper, to taste
• 2 cups canola oil
• 2 cups flour
• 2 tbsp. Spanish paprika
• 1 tsp. garlic powder
• 4 eggs, lightly beaten
• 2 cups panko bread crumbs
• 4 boneless, skinless chicken thighs, pounded until ¼" thick
• 8 tbsp. unsalted butter
• 1 bunch rosemary
• 1 bunch thyme
• 1 loaf challah bread, sliced 1” thick and toasted
• Apple sauce, for serving