For the roasted garlic: Preheat the oven to 350 degrees F. Using a basting brush, coat the garlic with the olive oil, place on a baking sheet, cover with aluminum foil and roast until the garlic lightly browns and softens to the touch, about 1 1/2 hours. Let cool, then roughly cut and set aside.
For the sauce: In a large saute pan (12- to 14-inch nonstick preferred) on medium-high heat, add the roasted garlic, butter and onions and saute until the onions are translucent, about 2 minutes. Add the heavy cream, wine, clams, salt and pepper and bring to a boil. (Do not walk away as cream has a tendency to boil over.) As the cream starts to boil, adjust the flame to a lower setting to prevent it from boiling over. Simmer the sauce until more than half of the clams have opened; The sauce will have reduced and thickened by almost half. Add the crabmeat, scallops and shrimp and simmer until the shrimp starts to curl up and the scallops start to swell, about 1 1/2 minutes per side. Add the Romano, Parmesan and green onions. The sauce will immediately start to thicken. Simmer for just about 1 minute to incorporate the Romano and Parmesan cheeses. Remove from the flame and serve over your favorite pasta.
This recipe was provided by a chef, restaurant or culinary professional. It has not been tested for home use.