Heat a large skillet over medium-high heat. Add the oyster mushrooms to the dry pan and cook for a few minutes until they begin to brown and release their moisture. Season with salt and pepper and continue sautéing until the mushrooms are golden and crispy.

Add the olive oil and butter to the pan. Stir in the sliced garlic and red pepper flakes and cook for about 30 seconds, until fragrant.

Add the chopped kale and sauté until wilted and tender, about two to three minutes.

Stir in the parsley and adjust seasoning with additional salt and pepper if needed.

Serve warm as a savory side dish.