Melt butter in a Dutch oven over medium heat. Working in batches, add shrimp and garlic; season with salt and pepper, to taste. Cook, stirring occasionally, until pink, about 2-3 minutes.
Stir in lemon zest and lemon juice; set aside and keep warm.
for the orzo
Melt butter in the Dutch oven. Add garlic and shallots, and cook, stirring occasionally, until tender, about 3 minutes.
Whisk in flour until lightly browned, about 1 minute.
Stir in wine and chicken stock, scraping any browned bits from the bottom of the Dutch oven. Stir in orzo; season with salt and pepper, to taste.
Bring to a boil; reduce heat and simmer, stirring occasionally, until pasta is cooked through, about 6 minutes.
Stir in Parmesan, heavy cream, lemon juice, parsley and dill; season with salt and pepper, to taste. Return shrimp to the Dutch oven.