Step 1
Peel and devein the shrimp reserving the shells and heads. Chop the shrimp into bite-size pieces.
Step 2
To make the shrimp stock combine the shrimp shells and heads onion and celery in a large pot. Squeeze the lemon juice into the pot then add the lemon halves as well. Add the dried basil oregano thyme peppercorns 1/2 cup parsley and 3 cups of water. Cover the pot and bring to a boil. Reduce heat and simmer uncovered for 1 hour skimming away any foam or impurities that have risen to the surface. Strain the shrimp stock and set aside.
Step 3
Heat the butter in a large skillet over medium heat. Cook the shrimp pieces until pink and almost cooked through 1 to 2 minutes. Remove and set aside. Add the shallots to the pan; cook and stir until the shallots have softened and turned translucent about 5 minutes.
Step 4
Stir in the garlic lemon zest salt and ground pepper. Cook for thirty seconds then add the white wine. Bring to a boil and cook until the white wine is reduced by half about 5 minutes. Add the shrimp stock to the pan bring it to a boil and simmer until the sauce is reduce by half about 15 minutes.
Step 5
Meanwhile fill a large pot with heavily salted water and bring to a rolling boil over high heat. Once the water is boiling stir in ravioli and return to a boil. Cook uncovered stirring occasionally until the ravioli float to the top and the filling is hot 3 to 4 minutes. Drain well reserving a little pasta-cooking water to thin the sauce if necessary.
Step 6
Stir the diced tomatoes and cream into the shrimp sauce and heat through. Return the shrimp to the pan taste the sauce and season to taste with salt and pepper. Fold the ravioli into the sauce.
Step 7
Place four ravioli onto each of four warmed pasta bowls or plates and top with sauce. Garnish the pasta with chopped parsley and lemon zest.