Preheat the oven to 425ºF.
Add the cauliflower, shallots and garlic to a large mixing bowl. Drizzle with olive oil and spices and toss to combine. Transfer veggies to a baking sheet and roast for 30 minutes, flipping halfway through.
Once roasted, transfer veggies to a saucepan. Add lentils, broth, and 2 cups of milk, and stir to combine. Bring the mixture to a boil, then cover and reduce to simmer for 20 minutes.
Remove from heat and blend until smooth. Stir in the remaining milk.
Serve immediately and top with desired garnishes.