Bring a large saucepan of salted water to a boil and add pasta squares. Stir well to prevent them from sticking together and cook for less than half a minute. Drain and transfer partially cooked pasta to a large bowl of ice water. Once cooled, transfer to damp kitchen towels and cover until ready to assemble the cannelloni.
In a saute pan melt 4 tablespoons of the butter along with the olive oil and saute onion until softened, about 6 minutes. Add garlic and cook for 2 minutes longer. Transfer to a mixing bowl and add lobster, shrimp, crabmeat and chopped herbs. Gently toss to combine.
Preheat the oven to 375ºF.
Assemble the cannelloni by placing a small amount of the filling in the center of each pasta square and roll up, cigar fashion. Repeat with the remaining cannelloni. Lightly oil a large casserole dish and arrange filled cannelloni, seam side up. Set aside while you make the sauce.
In a small saucepan melt remaining 4 tablespoons of butter and whisk in flour. Cook for 2 minutes, stirring frequently. Add the milk and whisk to combine well. Bring to a boil, stirring frequently, and cook for 5 minutes, until very thick and the floury taste is gone. Season to taste with salt, pepper and truffle oil. Pour sauce over top of cannelloni, sprinkle with grated cheese and bake in a preheated oven for 20 to 25 minutes, until heated through, bubbly and golden brown on top.
Yield: 6 servings
SPINACH PASTA DOUGH:
In the bowl of a food processor combine the flour, salt and blanched spinach. Process to mix well. With the machine running, add the eggs, egg yolks and olive oil through the feed tube, and process until it resembles wet corn meal, about 2 minutes.
Take a handful of dough at a time and form into a firm ball. Repeat with the remaining dough. Roll out each dough ball into desired shape in a pasta machine according to the manufacturer’s instructions.
Bring a pot of salted water to the boil and cook the pasta until just al dente, about 2 minutes. Drain in a colander and serve with desired sauce.
Yield: about 1 3/4 pounds fresh pasta