Direction

1. Melt butter with olive oil in a large pot over medium-low heat; stir in onion and sauté until translucent, about 5 minutes. Whisk flour into butter mixture; whisk in half-and-half and juice from drained clams.
2. Stir Parmigiano-Reggiano cheese into onion mixture until melted, about 2 minutes; stir in potatoes, cream-style corn, corn kernels, and cherry tomatoes. If soup is very thick, stir in water, about 1/2 cup at a time, as desired; bring soup to a simmer and cook until potatoes are tender, about 15 minutes. Season with sea salt and pepper.
3. Stir drained clams, haddock, and shrimp into soup; simmer until haddock and shrimp are fully cooked for 5 minutes. Stir in lobster and its juice; cook just until heated through.