Rinse the rice under cold water in a fine-mesh sieve until the water runs mostly clear (helps reduce surface starch). Drain well. Slice mushrooms, finely chop the onion, and mince the garlic.

Sauté aromatics

In a medium saucepan or deep skillet with a tight-fitting lid, heat 1 tablespoon olive oil and 1 tablespoon butter over medium heat until butter melts and foams. Add the chopped onion and a pinch of salt; cook, stirring occasionally, until the onion is soft and translucent, about 4–5 minutes. Add the minced garlic and cook 30–45 seconds until fragrant.

Brown mushrooms

Increase heat to medium-high, add the sliced mushrooms and the remaining 1 tablespoon butter. Spread mushrooms into a single layer and let them brown without stirring for 2 minutes, then stir and continue cooking until they release their liquid and most of it evaporates, about 4–6 minutes. Season with 1/2 tsp black pepper and the dried thyme. If using soy sauce, add it now and stir to glaze the mushrooms.

Toast rice

Add the rinsed, drained rice to the pan with the mushrooms and stir to coat the grains in fat and mushroom juices. Toast the rice for 1–2 minutes, stirring constantly, until edges look translucent.

Simmer

Pour in 3 cups of water or broth and add 1 teaspoon salt. Bring to a gentle boil over medium-high heat. Once boiling, reduce heat to low, cover tightly, and simmer undisturbed for 15 minutes (for jasmine) or 18 minutes (for long-grain white). Do not lift the lid while rice cooks.

Steam

After the cooking time, remove the pan from heat and keep it covered. Let the rice steam for 10 minutes to finish cooking and to become fluffy.

Fluff

Remove the lid, fluff the rice gently with a fork to separate grains and evenly distribute mushrooms.

Finishing & Garnish

Stir in 2 tablespoons chopped fresh parsley and 1 teaspoon lemon zest, if using. Taste and adjust seasoning with more salt or pepper if needed. If desired, sprinkle 2 tablespoons grated Parmesan over the rice and fold gently to incorporate. Serve warm.