In a large pan over medium heat, melt butter. Pat shrimp dry and season to preference with salt and pepper. Add a single layer of shrimp to the pan, cooking for 2-3 minutes on each side or until cooked through. Once cooked, remove to a bowl and set aside.
Add a tablespoon of olive oil to the same pan, add in onion and garlic. Sauté for about 2 minutes until fragrant. Add in orzo and sauté another 30 seconds to lightly toast.
Stir in bone broth and bring to a low simmer, stirring often, then reduce to low heat. Cover to cook for about 15 minutes, or until pasta is al dente. Stir occasionally.
For the last 5 minutes, stir in asparagus cooking until tender.
Once cooked, remove from heat. Stir in shrimp, lemon juice, and grated parmesan cheese.