1
Adjust rack to top position and preheat oven to 425 degrees. Wash and dry produce.
Cut potatoes into ½-inch-thick wedges. Trim and thinly slice mushrooms (skip if your mushrooms are pre-sliced!). Halve, peel, and thinly slice onion.
Toss potatoes on a baking sheet with a large drizzle of oil, half the Ranch Spice (all for 4 servings), salt, and pepper. Roast on top rack until browned and tender, 18-20 minutes.