Boil a litre of water in a medium saucepan. Cover and simmer on a low flame while you make the risotto.
Rinse and parboil the barley in a saucepan on high heat for 10 - 15 minutes. Use double the quantity of water. Drain and save 1 cup of the water.
In a saucepan, heat the olive oil with 1 tbsp butter. Add the onions and garlic and sauté. Add one cup of mushrooms, season well with salt and pepper and cook further.
Add the barley and toast for 2 mins. Add the wine and allow to evaporate.
Add a cup of hot water and ½ cup of the barley water and cook the barley, covered, on a high flame, stirring occasionally. As the water gets soaked, add the remaining barley water and more hot water. After 15 minutes, the barley should be cooked 3/4th of the way. The barley should be al dente (soft with a bite). Remove the lid and cook.
In the meantime, in another pan, sauté the remaining mushroom with some garlic and parsley till brown. Keep aside
Once the rice is cooked, stir in the mushrooms.
Take off heat and stir in the remaining butter, parmesan. Garnish with some parsley. Allow to stand for 2-3 mins and serve hot.