1 large head of cauliflower, trimmed
1 lb yukon gold potatoes, scrubbed (I use yukon because of the waxy/creamy quality)
2 cooking onions, papery skin removed
1 sprig of fresh rosemary (mine was particularly lush, so perhaps 2 normal sprigs is advisable)
2 tbsp oil
salt and pepper
juice of 1/3 of a lemon (like 2 teaspoons)
5-6 cups vegetable stock
some kind of flavourful oil (truffle, extra virgin olive, walnut etc)
toasted + chopped nuts
chopped leafy herbs
squeezes of lemon
flaky sea salt or fresh pepper
Preheat the oven to 400 degrees F.
Remove the core from the cauliflower and chop it into rough florets. Place the florets into a 9 x 13 glass baking dish.
Chop the potatoes into pieces about half the size of the cauliflower florets and toss them into the baking dish as well.
Chop the onions into rough 1-2 inch pieces and toss them into the dish. It doesn’t matter if the layers stick to each other.
Remove the leaves from the rosemary sprig and chop/mince them up. Sprinkle the rosemary over the vegetables in the dish. Liberally salt the vegetables and season with pepper to taste. Add the oil and toss the vegetables until evenly coated with the oil, herb and seasoning.
Roast vegetables for about an hour, flipping and tossing them here and there with a metal spatula/spoon to promote even browning. When done, remove from the oven and squeeze the 1/3 lemon over the hot vegetables (I just drop the lemon into the warm pan when I’m done so that it can release some oil too). Using your metal spatula, toss the vegetables with the lemon juice, scraping the browned bits off the bottom.
Once the vegetables are cool enough for you to handle, start blending them in batches with the stock. Purée until smooth and pour into a big soup pot. Continue blending in batches until you’ve used up everything. Heat the large soup pot full of purée over medium heat until it boils. Add more stock or water to thin the soup out if necessary and adjust seasoning to taste. Serve hot with optional garnishes.