Microwave the French green beans in a microwave-safe dish, adding a splash of water. Cover and cook on high for about 8-10 minutes, until they are bright green and almost tender. Drain any excess water and set aside.

In a large skillet, pour in the olive oil and add the butter. Heat over medium-high heat until the butter is melted and bubbling.

Slice the chicken thighs into bite-sized pieces, season with salt and lemon pepper, and cook in the skillet for about 4 minutes on each side until golden-brown.

Stir in the minced garlic and onion powder, then add the pre-cooked green beans and sliced mushrooms. Sauté for about 4-5 minutes.

Pour in the chicken broth and heavy cream, stirring well. Bring to a simmer and cook until it thickens slightly.

Stir in the Parmesan cheese until it melts into the sauce, adjusting seasoning as needed.

Transfer to a serving dish, garnish with chopped parsley, and serve hot over rice or mashed potatoes.