Preheat oven to 400° F. Spread cauliflower, leeks and garlic on a baking sheet. Drizzle with 2 tablespoons olive oil and toss well to coat everything, sprinkle with salt and pepper and toss again.
Roast for 20-25 minutes, rotating halfway through. Remove when everything is starting to turn golden, the leeks will darken which is fine.
Add the roasted veggies, drained cashews, miso, thyme leaves, 2 cups of water or broth and lemon juice to a high speed blender or food processor and blend for 1 minute. Add the other 2 tablespoons of olive oil, paprika, red pepper flake and the rest of the water or broth and blend until smooth.
Pour into a medium saucepan and heat just until it’s warm (no need to bring to a boil). Stir in a little more water if it’s too thick and season if needed with additional spices. Serve with a drizzle of olive oil.