Add chicken stock to the skillet, scraping up the browned bits at the bottom of the pan. Add 1/4 teaspoon of salt and stir.
Place chicken legs back in the pan.
Bring the chicken stock to boil, cover, and reduce heat to simmer on low-medium.
Simmer chicken legs for 25-30 minutes, until the chicken is completely cooked through and the juices run clear when chicken is cut in the middle.
Remove the cooked chicken legs to a plate and keep warm.
Turn the heat under the skillet to medium-high, and simmer the mushroom sauce for about 4 minutes until it is reduced by about a third.
Stir in the 1/2 cup heavy cream into the mushroom sauce and simmer for another 2 minutes on low-medium heat, constantly stirring and scraping from the bottom of the skillet, until the sauce gets thicker.
Add chicken legs back to the skillet to warm them up.