In a large skillet over medium heat, add the oil and the butter. Let the butter melt completely and begin to froth.
Add the mushrooms and sauté 2 minutes, then add the zucchini and sprinkle with the seasoning. Continue to cook, stirring frequently, until the vegetables are tender and a little browned.
Stir in the thawed cauliflower florets and toss to combine. Cook until warmed through, another 2 minutes or so.
Taste and add salt or additional steak seasoning as desired.
