Clean the lion's mane mushrooms under cool running water, brush off any debris, and pat completely dry with paper towels.

Tear the mushrooms into bite-sized pieces by hand, following their natural grain.

Heat a large skillet over medium-high heat for about 1 minute until hot.

Add 1 tablespoon olive oil and 1 tablespoon butter to the pan and swirl to combine.

Add half of the mushroom pieces in a single layer and cook undisturbed for 3 to 4 minutes until golden brown.

Stir and cook for an additional 2 to 3 minutes until tender, then transfer to a plate and repeat with remaining oil, butter, and mushrooms.

Return all mushrooms to the pan, add sliced garlic and fresh thyme, and cook for 1 minute until fragrant.

Optional: pour in white wine or broth to deglaze the pan, scrape up browned bits, and reduce by half over 1 to 2 minutes.

Remove from heat, stir in lemon juice, season with salt, black pepper, and red pepper flakes, then transfer to a serving dish and garnish with chopped parsley.