• Bring a large pot of salted water to a boil to cook the pasta

Prepare the sauce:

• Preheat a large skillet and add 3 Tbsp of olive oil over medium heat. Saute the smashed garlic and onion until the onions are soft and caramelized a bit, about 3 minutes or so, until they smell really good.
• Add the quartered tomatoes and smash them with the spatula as you cook them for another 3 minutes or so. Transfer the mixture into a food processor or blender and blend into a puree.
• To the same skillet, add about 1 Tbsp of oil. Add the shrimp and saute until they turn opaque and dish them out and set aside. Pour the tomato puree mixture you prepared earlier. Add the minced clam with its juice, tomato paste, sugar and pinch of salt. Bring it back to a boil and then cover and lower the heat to let it simmer for about 15 minutes or so.
• During the last 5 minutes, add the mussels to the sauce. Cover again and let them cook for about 5 minutes. Uncover and the shells should have opened up. Discard the ones that remain shut.

Cook the pasta:

• When the water is boiling, cook the linguine as directed on package. Cook it to al dente. Reserve about 1 cup of the cooking water and drain off the rest. Do not rinse the linguine. Set is aside

When ready to serve:

• Add the cooked shrimp and cooked linguine to the sauce. Toss to combine everything. You may add more of the reserved pasta water to loosen up the sauce a bit if needed. The clam sauce should be somewhat a bit loose but not runny. Have a taste and season according to your preference. Turn off the heat and transfer to a large serving platter and serve family-style