Step 1

In a Dutch oven, heat butter over medium-high heat. Add red onion and mushrooms; saute for 4-5 minutes or until tender. Add garlic; cook 1 minute longer. Stir in the flour, salt and pepper until blended; add tomato paste. Gradually whisk in broth; bring to a boil. Reduce heat; cover and simmer for 5 minutes.

Step 2

Add clams and shrimp; return to a boil. Reduce heat; simmer, uncovered, 5-10 minutes longer or until shrimp turn pink, stirring occasionally. Stir in crab and cream; heat through (do not boil). Serve with cheese and green onions.