Combine beef broth, chicken bouillon, soy sauce, onion powder, mustard powder, and thyme. Set aside.

Combine cornstarch with 3 Tablespoons of cold water in a sealable container and shake to combine. Set aside in a cool place.

Gently rinse mushrooms and pat completely dry. Slice if needed.

Slice the chicken lengthwise into 2-3 thinner slices. Pound with a meat tenderizer if needed, the chicken will plump up more when cooked. Aim for ½ inch thick slices.

Melt butter over medium-high heat and add the mushrooms. Allow them to brown on each side for 3-4 minutes, undisturbed. Remove once golden brown and set aside.

Lightly sprinkle each side of the chicken with salt and pepper. Dredge in flour and tap off excess.

Heat olive oil in a large pan over medium-high heat. Add chicken, sauté for 4-5 minutes per side, until golden brown. Repeat with remaining chicken.

Make slight adjustments to heat as needed during cooking.

Turn the heat off and remove excess oil, but leave the brown bits in the pan. Add white wine and garlic, set heat to medium. Let bubble gently until reduced by half, about 4 minutes.

Add the beef broth mixture and increase heat slightly to bring to a gentle boil. Let it bubble and reduce for 10 minutes.

Shake the reserved cornstarch mixture and slowly add it to the bubbling sauce, stirring continuously until incorporated.

Slowly add in the cream, stirring continuously. Add the mushrooms. Add the chicken back to the pot along with any juices from the plate. Spoon the sauce on top. Cover partially and let heat through for 5 minutes.