Spread the cauliflower florets and unpeeled garlic cloves on a baking sheet. Drizzle with olive oil and season with salt and pepper. Toss to coat evenly.
Roast in the preheated oven for about 25-30 minutes, or until the cauliflower is tender and the garlic is soft and lightly golden.
Remove from the oven and let cool slightly. Squeeze the roasted garlic out of its skins into a bowl.
In a food processor, combine the roasted cauliflower, roasted garlic, cream cheese, milk, nutmeg, and a pinch of salt and pepper. Blend until smooth and creamy to your desired consistency.
Taste and adjust seasoning if necessary. If it feels too thick, add a bit more milk until the desired texture is achieved.
Transfer the mashed cauliflower to a serving bowl and garnish with chopped chives or parsley.
Notes
For a vegan version, substitute cream cheese and milk with plant-based alternatives.