Created by lazyme on February 20, 2015
Step 1: Preheat oven to 350.
Step 2: In a medium-size saucepan, melt butter over medium heat.
Step 3: Stir in flour and cook, stirring, for 1 minute without browning.
Step 4: Whisk in milk, bring to a boil, and cook, stirring, until sauce is thick and smooth, about 3 minutes.
Step 5: Stir in horseradish, sour cream, sugar, mustard, and vinegar.
Step 6: Season with salt and pepper to taste.
Step 7: Arrange chicken breasts, skin side up, in a baking dish.
Step 8: Spoon half the horseradish sauce over chicken.
Step 9: Bake 45 minutes until chicken is tender.
Step 10: Broil chicken for 5 minutes to brown.
Step 11: Reheat remaining sauce and serve over chicken.