Trim stems of mushrooms so that only caps remain. In a large skillet heat butter and olive oil together over medium-high heat. Place mushrooms in pan in single layer. Sauté for 5 minutes or until beginning to brown.
Flip mushrooms and sprinkle with garlic powder, salt, and pepper. Sauté for 5 more minutes.
Add soy sauce, lemon juice, stock, and thyme. Cook for 2-4 more minutes or until liquid has mostly cooked off. Garnish with parsley and serve alongside potatoes, steak, chicken, or pork chops.