Step 1

Heat the olive oil and 1 tablespoon butter in a medium saucepan. Add the barley and cook over medium heat, stirring constantly, until the barley smells toasty, about 5 minutes.

Step 2

Add the lemon zest, 3 sprigs thyme, and chicken stock. Bring to a simmer, cover, and reduce the heat to low. Cook for 30 to 35 minutes, stirring occasionally. When most of the water is absorbed, add the chopped parsley.

Step 3

Remove the stems of shiitake mushrooms and discard. Slice the mushrooms into 1/4-inch wide strips. Heat the remaining 2 tablespoons butter in a saucepan. Add the onions and cook until tender, about 5 minutes. Add the mushrooms and the remaining 3 sprigs thyme and continue to cook until brown, 8 to 10 minutes.

Step 4

Spoon the barley into warm bowls and top with the mushrooms. Sprinkle the Parmesan over the top. Garnish with parsley leaves and serve hot.