Preheat oven to broil.
Cut cauliflower into large wedges.
Place cauliflower and potato into a baking sheet.
Add white wine, oregano, rosemary, thyme, and crushed red pepper flakes to the baking sheet.
Rub tri tip with mustard, then season with salt, black pepper, and garlic powder.
Add garlic to the baking sheet, then season the potato and cauliflower with salt and pepper. Place the tri tip on top of the potato and cauliflower.
Place the baking sheet under the broiler until a crust begins to form on the tri tip. Broil for 3-4 minutes.
Flip the tri tip and change oven temperature to 375 degrees. Roast the tri tip for 45 minutes, or until it reaches the desired doneness.
Let the tri tip rest before slicing.