In a large skillet over medium-high heat, melt the butter and allow the butter to bubble and sizzle until the colour turns a light golden/brown colour.
Add the mushrooms, shallots, salt, and black pepper. Toss to coat with the butter.
Saute the mushrooms and shallots until deep brown in colour - about 12 minutes - stirring often.
Once the mushrooms are browned, add the Worcestershire sauce and thyme leaves. Toss to combine and saute for another 2-3 minutes.
Remove from skillet and transfer to a plate. Garnish and serve immediately.