Preheat oven to 400 degrees.
Cut/break cauliflower into pieces and place into a large bowl.
Drizzle olive oil over cauliflower, pour in ranch packet/homemade seasoning mix, salt and pepper (to taste). Mix well until all cauliflower is coated well.
Spread onto baking sheet (lined with parchment paper ideally, aluminum foil works too).
Bake for 20-30 minutes, or until cauliflower starts to brown nicely.