In a small pan, heat the olive oil over medium heat. Add the mushrooms and onions. Saute until the vegetables are tender, 4 to 6 minutes. Add the garlic and saute another minute — taking care not to burn the garlic. Add the wine and cook until it evaporates completely, about 1 minute.
In a pot fitted with a steamer basket, bring 1 inch of water to a boil. Add the asparagus. Cover and steam until tender-crisp, 2 to 3 minutes. Set aside.
In a small bowl, add the blue cheese, balsamic vinegar, water and black pepper. Whisk to mix thoroughly. (Just before drizzling the dressing over the salad, whisk again.)
Add 3 cups of lettuce to each plate. Top each with 1/2 of the mushroom mixture, 1/2 of the asparagus, 1 roasted red pepper, 1/2 of the blue cheese dressing mixture and 1/4 cup croutons. Serve immediately.