Soak the dried porcini in 250ml of hot (not boiling) water for 15 minutes. Lift the mushrooms out with a fork, squeeze gently, and chop roughly. Strain the soaking liquid through a fine-mesh sieve into a measuring jug and set aside.

Warm the olive oil in a large heavy-bottomed saucepan over medium-high heat. Add the cremini mushrooms in a single layer and cook without stirring for 2-3 minutes until golden on the bottom. Stir and cook another 2 minutes, then transfer to a plate.

Reduce the heat to medium. Add the diced onion to the same pan with a pinch of salt. Cook for 5-6 minutes, stirring occasionally, until soft and translucent. Add the minced garlic and thyme leaves and cook for 1 minute until fragrant.

Add the rinsed pearl barley to the pan and stir to coat in the oil and onion mixture. Toast for 2 minutes, stirring frequently, until the barley smells slightly nutty.

Add the chopped porcini, the strained porcini soaking liquid, and the vegetable stock to the pan. Drop in the bay leaf. Stir to combine, then season with 1 tsp salt and the black pepper.

Bring to a boil, then reduce the heat to low. Cover with a tight-fitting lid and simmer for 35-40 minutes, stirring once or twice, until the barley is tender and has absorbed most of the liquid. If it looks dry before the barley is done, add stock in 50ml increments.

Stir the golden cremini mushrooms back into the pan. Cover and rest off the heat for 5 minutes.

Remove the bay leaf. Stir in the lemon zest and chopped parsley. Taste for salt, adjust, and serve hot.