Prep everything first: warm the stock in a saucepan over low heat and keep it at a gentle simmer. Have your rice measured, cauliflower riced (if using a head, pulse in a food processor until pea-sized), mushrooms cleaned and sliced, and onion and garlic minced. WHY: keeping the stock hot prevents shocking the rice and helps it cook evenly without lowering the pot temperature each ladle; mise en place speeds cooking and prevents overcooking delicate elements.

Sweat the onions: in a wide sauté pan (at least 12-inch/30 cm) heat 1 tablespoon olive oil over medium heat. Add the diced onion and a pinch of salt and cook, stirring, until translucent but not browned, about 4–5 minutes. WHY: gently sweating the onion releases sweetness and builds a flavor base. Avoid high heat here because browned onions will change the intended delicate flavor.

Add the garlic and a little butter: add the minced garlic and 10 g (about 2 teaspoons) butter and cook 30–45 seconds until fragrant. WHY: garlic cooks very quickly and adds aromatic depth; adding a bit of butter now helps carry flavor and creates a glossy mouthfeel later.

Toast the Arborio: add the 65 g Arborio rice and stir to coat in the fat and aromatics for 60–90 seconds. You'll hear a faint pop as the outer starches toast. WHY: toasting briefly coats each grain in fat, slightly toasts flavor compounds and helps the rice absorb liquid more evenly while preserving some bite.

Begin ladling warm stock: add one ladle (about 120 ml) of warm stock and stir constantly until the liquid is nearly absorbed. Continue adding stock, one ladle at a time, stirring and allowing the rice to absorb before adding more — total for the Arborio portion will be about 300–360 ml of the stock (you won't need the full 960 ml for the rice alone). WHY: constant stirring and incremental liquid release starch from the rice creating the classic creamy risotto texture without overcooking; adding too much liquid at once prevents proper starch release.

Cook the cauliflower 'rice' separately: while the Arborio cooks (after about 8–10 minutes from first ladle), heat a separate large skillet over medium-high with the remaining 1 tbsp olive oil and the rest of the butter (about 16 g). Add the sliced mushrooms and a pinch of salt and cook without stirring for 2 minutes to let them brown, then stir and cook another 3–4 minutes until deep golden. WHY: cooking the mushrooms in a hot pan and letting them sit briefly achieves Maillard browning and concentrated mushroom flavor — if you constantly stir you’ll steam them and miss that depth.

Add riced cauliflower to the mushrooms: add the riced cauliflower to the mushroom pan, season with salt and pepper and the thyme if using. Cook, stirring, 4–6 minutes until the cauliflower is tender but not mushy and has lost its raw edge. WHY: separately cooking cauliflower lets it develop a little texture and caramelization so it doesn't turn watery when combined with the rice; it also concentrates flavor.

Combine rice and cauliflower: when the Arborio is al dente — creamy outside but still with a faint ‘tooth’ in the center (about 14–16 minutes into cooking) — fold the cauliflower-mushroom mixture into the rice. Stir to combine and add a few more splashes of hot stock to marry the textures if needed. WHY: combining at this point keeps the cauliflower from overcooking and lets the rice starch act as a binder, giving a cohesive, creamy finish while keeping carbs lower.

Finish with cheese and butter: remove the pan from heat and stir in the grated Parmesan and the remaining butter (if any) until glossy. Taste and adjust seasoning with salt and pepper. Let the risotto rest for 1–2 minutes; it will thicken slightly. WHY: finishing off-heat with butter and cheese emulsifies the sauce and brings shine, mouthfeel and umami; resting allows the starches to settle so you can serve at the perfect consistency.

Plate and garnish: divide into warm bowls, top with a few reserved browned mushroom slices or a small sprinkle of grated Parmesan and a crack of fresh black pepper. Serve immediately. WHY: risotto is best hot and slightly loose; if it sits too long it becomes stodgy as it cools.