Heat 2 tbsp butter in a large pot or Dutch oven over medium heat and add the shrimp. Saute until the shrimp are pink and cooked through. Transfer to a plate and set aside.

Add the avocado oil to the pot and heat over medium heat. Add the onion and cook until translucent, about 2-3 minutes. Add the garlic and cook another 30 seconds.

Carefully pour in the broth, cream, lemon juice, lemon zest, Italian seasoning, salt, and pepper and stir until combined. Bring to a boil, then reduce to a simmer and add the linguine. Cook uncovered for 10 minutes, stirring occasionally.

After 10 minutes, stir in the frozen peas, cover, and cook an additional 5-6 minutes, or until the pasta is al dente.

Remove from heat and stir in the shrimp. Garnish with shaved parmesan if desired, then serve.