In a large 10 in sauce pan heat olive oil over medium heat

Add chicken breasts, and sear on all sides, once seared, turn heat down to low, cover and cook for 10 min

Remove chicken, cut into 1 in pieces. It's ok if the chicken isn't completely cooked through, it will finish in the simmering phase at the end.

Add onions and garlic. Saute until onions are translucent.

Add flour and chick broth. Whisk together until smooth.

Now add mushrooms and butter, saute for 5 min

Add chicken back to the pan, add seasonings. Simmer for another 10 min until sauce comes together