Wipe mushrooms clean with damp paper towel (don't wash)
Trim stems if needed, halve or quarter large mushrooms
Heat large skillet over medium-high heat 2-3 minutes
Add 4 tbsp butter, let melt and foam
Add mushrooms in single layer (don't overcrowd)
Let sit undisturbed 3-4 minutes to brown
Stir, let cook another 3-4 minutes without moving
Add minced garlic and remaining 2 tbsp butter
Stir well, cook 1-2 minutes until garlic fragrant
Add Worcestershire, garlic powder, onion powder, salt, pepper, and thyme
Toss to coat evenly
Cook 2-3 more minutes, stirring occasionally, until tender and golden
Taste and adjust seasoning
Transfer to serving dish, garnish with parsley
Serve immediately