Sprinkle the chicken breasts with the onion salt and black pepper, making sure to coat both sides.
Heat the olive oil in a large frying pan over medium heat and sear the chicken breasts for approx. 3 minutes on each side or until golden brown. Then remove them from the pan and set them aside.
In the same frying pan, mix the cornstarch with a few tablespoons of the chicken stock until smooth. Then gradually add the remaining chicken stock, whisking as you go.
Heat the pan on a medium setting again, and add the mustard and honey, whisking until combined.
Once the sauce is bubbling, stir in the milk and cream and allow to return to a boil. Season to taste.
Return the chicken breasts to the pan and add the broccoli. Cover and reduce to a simmer. Cook for a further 10 minutes.
Garnish with chopped fresh parsley if desired.
