Slow-Cooker Chicken Breasts With Creamy Mustard-Leek Sauce

Ingredients

For the Marinade

• 1/3 cup mayonnaise
  
• 2 tablespoons cider vinegar
  
• 1/2 teaspoon salt, plus more for the slow cooker
  
• 1 tablespoon fresh rosemary, finely minced
  
• 1 tablespoon fresh sage, finely minced
  
• 2 boneless, skinless chicken breasts
  

For the Slow Cooker

• 1 shallot, finely minced
  
• 1 leek, trimmed and cleaned, cut into thin half moons
  
• 3/4 cup chicken stock
  
• 1 tablespoon cornstarch
  
• 1 tablespoon whole-grain mustard
  
• 2 tablespoons dry white wine
  
• 1/3 cup heavy cream
  
• 12 ounces egg noodles
  
• 3 tablespoons butter
  
• 1 handful fresh chives, finely chopped
  

Directions

1. To make the marinade, add all the marinade ingredients except the chicken to a mixing bowl. Stir to combine. Nestle the chicken in the marinade. Cover and store in the refrigerator overnight.
2. Add the shallot and leek to the slow cooker, along with a pinch of salt. Add the chicken stock and cornstarch to the slow cooker, and stir to combine. Make sure the cornstarch is dissolved in the chicken stock with no lumps. Add the mustard, white wine, and heavy cream, stirring once more to combine everything.
3. Add the marinated chicken to the slow cooker, discarding any excess marinade. If some marinade and herbs are clinging to the chicken when you add it to the slow cooker, that's fine. Set the slow cooker to low, and cook for 2 1/2 hours. When about 2 hours have passed, boil water in a large pot and cook the egg noodles according to the directions on the package. Toss the cooked egg noodles with butter and set aside.
4. After 2 1/2 hours, check to see if the chicken is fully cooked. If it's less than 165°F at its thickest point, continue cooking. Check the chicken every 15 minutes until it's fully cooked.
5. When the chicken is fully cooked, transfer it to a cutting board and slice it into medallions. Taste the sauce in the slow cooker. Add more salt as needed.
6. To serve, arrange some chicken atop a portion of egg noodles. Top with sauce. Garnish with chives.