Cut the chicken breasts in half, cover with cling film and beat with a hammer.
Combine flour, garlic, salt and pepper. Then roll each piece of chicken in this mixture.
Fry the chicken in hot oil on both sides, until golden brown. Remove from the pan.
Add the rest of the butter to the pan. Fry mushrooms until golden and until excess moisture evaporates.
Add shallots, garlic, mix, cook until soft.
Pour in the wine, mix to warm it. Add thyme, chicken stock, mustard and heavy cream. Bring to a boil and cook for 5 minutes.
Pour in the starch dissolved in water, mix. Return the chicken to the pan and cook until the sauce thickens.
Remove the thyme, then salt and pepper. Sprinkle with parsley and serve