Preheat oven to 425 degrees. Place chopped cauliflower and sliced garlic into a bowl. Drizzle cauliflower with melted coconut oil and stir to coat the cauliflower with the melted coconut oil. Line a baking sheet with aluminum foil. Place cauliflower onto foil-lined baking sheet. Roast cauliflower for about 25 to 30 minutes. Season to taste with salt and pepper before serving.