or the garlic butter: Remove butter from refrigerator, unwrap, place in mixing bowl, and then let sit at room temperature for 1 hour to soften. After 1 hour, stir in olive oil, parsley, garlic, and lemon. Season with salt and pepper. Use a rubber spatula to mix and scrape down the sides of the bowl to make sure all ingredients are blended. Taste and adjust seasoning with salt and pepper. Cover bowl tightly with plastic.
For the pasta: Fill a 6-quart soup pot halfway with water and place over medium-high heat. Add salt and bring to a boil. Once boiling, add the pasta and stir to keep from sticking together—about 5 to 7 minutes cook time (until al dente). While pasta is cooking, place a large skillet over medium-high heat. Add clams, wine, and shallots; cover and cook for 3 minutes. Add the broth; then return to a boil until clams open—6 to 8 minutes total cook time. Remove lid and transfer the open clams to a bowl and cover.
Meanwhile, simmer the pan juices over medium heat. Add the shrimp to the simmering juices and cook for 3 to 4 minutes. Transfer the cooked linguine directly to the skillet. Whisk in 4 to 6 ounces of whipped garlic butter mixture, and let simmer until sauce becomes slightly thick, 3 to 5 minutes. Add the tomatoes, and stir well to incorporate the garlic butter. Add the open clams and all their juices and toss well.
To assemble: Portion the pasta into individual bowls, and then divide and arrange seafood on top of pasta. Just before serving, spoon over the sauce and tomatoes. Serve immediately. Parmesan for grating over the seafood pasta is optional.