
In a large bowl, mix together all of the marinade ingredients. Add the chicken and toss with the marinade. Cover and chill in the refrigerator for at least 12 hours.
In the slow cooker, add the shallot and leeks and an extra pinch of salt. Stir in the chicken stock and cornstarch, stirring to dissolve the cornstarch. Stir in the mustard, mushrooms, white wine, and heavy cream. Then take the chicken out of the marinade (discard the extra marinade) and add it to the crockpot.
Cook on low for 2 1/2 hours. After 2 hours, boil water in a large pot on the stove and cook the egg noodles according to the directions on the package. Drain the noodles and toss the noddles with butter and set aside.
After 2 1/2 hours of cooking time, check the chicken, making sure the internal temp reaches 165℉. Once it's done, remove the chicken and cut into slices. Place the chicken over the noodles and garnish with fresh dill and chives. Serve immediately.