Bring chicken broth to a boil in a small saucepan and reduce to a light simmer.
Melt butter over medium heat in a high-sided skillet. Add garlic, onion and barley and sauté for 1-2 minutes, stirring constantly to allow the barley to toast slightly and the onions and garlic to soften.
Add 2 cups chicken broth. Cover and simmer for 5-6 minutes, stirring occasionally. Remove cover and add additional cup of broth, continuing to stir as needed.
When all liquid is absorbed add one more cup and repeat until there is about one cup of broth remaining.
Add ½ cup broth to the barley mixture along with the asparagus and shrimp. Stir and cover until all liquid is absorbed. Add last of the broth and stir until absorbed and shrimp and asparagus are fully cooked. Remove from heat and allow to cool slightly.
Add Lemon Avocado Oil Vinaigrette and toss. Season with salt and pepper to taste. Serve warm topped with freshly grated parmesan cheese, thyme and fresh lemon slices if desired.