1. In a medium size bowl, dissolve stock cube in boiling water.
2. In a large bowl, add egg, garlic salt, and pepper. Beat well.
3. Place a saucepan on flame, add pearl barley, and stock in it. Cover with lid and let it simmer for about 20 minutes or until done.
4. Meanwhile, in a frying pan melt butter and add chopped onions in it. Stir and cook until golden.
5. Throw mushroom into the frying pan, reduce the heat to low, and cook until brown. Stir occasionally.
6. Sprinkle salt and mix well. Turn off the heat and wait for pearly barley to cook.
7. Throw cooked pearl barley into the frying pan with onion and mushroom, Mix well.
8. Transfer the mixture into the bowl with beaten eggs. Mix to combine.
9. In the same pan, heat olive oil, and transfer egg mixture into it. Spread evenly. Cover, and cook for a few minutes.
10. Turn on grill, and place frying pan in it. Cook for 1-2 minutes.
11. On a serving platter transfer pancake, and serve it hot with a drizzle of tobasco sauce.