Turn your oven on to 425 degrees (no need to preheat). On a large rimmed baking sheet (affiliate link), toss the cauliflower with 2 tablespoons of the olive oil until lightly and evenly coated in oil. Arrange the cauliflower, onion, garlic (leave garlic whole) and chili flakes (if using) in a single layer and sprinkle with kosher salt (affiliate link) (a good 2 pinches). Roast until the cauliflower and onion is tender and caramelized on the edges, 25 to 35 minutes, tossing halfway.

Scrape cauliflower mixture into the jar of a blender (you want to be sure and grab those yummy caramelized bits-that’s flavor baby!) Add about a cup of chicken stock, blend until smooth 

Tip: hold the top of the blender or food processor (affiliate link) down with a towel, so not to accidentally burn yourself. Add the butter and blend until smooth, then add the milk. Add the vinegar and nutmeg and blend again. Pour blended mixture into a large saucepan and add remaining chicken stock Over medium-high heat, bring the mixture to a simmer. Cook, stirring occasionally, until all the flavors are acquainted, about 20 minutes.

Taste for seasoning, add more salt if needed. Be sure it is seasoned enough. Garnish filled bowls with green onions. (I always forget the garnish!) or roasted chickpeas (as photograhed) This soup keeps well in the refrigerator, covered, for about four days, or for a few months in the freezer.