Preheat oven to 400 degrees.
Heat 1 tablespoon oil in a small skillet or saute pan over medium-high heat. Add the cremini mushrooms and cook, stirring often until browned, approximately 5-6 minutes. Set aside.
Heat 3 tablespoons oil in large shallow pan over medium heat. Add the onions, reduce heat to low and cook 10-12 minutes or until soft and golden. Add the garlic, stir until fragrant.
Add the barley, 3 cups broth, tomato paste, basil and oregano. Bring to a boil, reduce heat to low and cook, uncovered, stirring frequently until barley is tender, approximately 20 minutes.
Add the spinach, Taleggio and Parmesan cheese and stir until spinach is wilted and cheese is melted. Stir in cooked cremini mushrooms. Season to taste with salt and black pepper. Keep warm.
Lightly brush Portobello mushrooms with remaining olive oil. Roast for 7-8 minutes or until mushrooms give up some of their water. Immediately flip the mushrooms over to drain for 1-2 minutes.
To serve, top Portobello mushrooms with equal amounts of the risotto. Top with additional grated Parmesan cheese and garnish with chopped fresh parsley or parsley sprigs.