Fill a large pasta pot halfway with salted, hot water and place it on the stove, covered, on high heat.
While the water is heating, make your clam sauce in a large skillet. Peel and chop the shallot. Heat the butter and olive oil in the skillet over medium-high heat. When melted, add the shallots, stirring a bit. Lower the heat to medium and let the shallots cook for a few minutes. Press or mince the garlic and stir it into the pan.
Add the wine, bay leaf, clam juice, salt and red pepper flakes to the skillet, and stir to combine. Lower the heat a bit until the pan is simmering gently.
When the water is boiling in your large pot, add the pasta and stir it in until it's submerged. Leave the lid off and cook the pasta until it's al dente, stirring occasionally to prevent sticking. (Check it for doneness three minutes before the al dente time listed on the package.) While the pasta is still cooking, use a ladle to scoop out about a cup of the pasta water to reserve in a separate bowl.
When the pasta is almost done, stir in the drained clams to your skillet with the clam sauce. Continue cooking the sauce just until the clams are heated through. Turn off the heat and stir in the lemon juice and parsley, if using.
When the pasta is done, drain it in a colander in the sink. Then add the pasta to the pan of clam sauce and toss to combine. Stir in ¼ cup of the reserved pasta water, (or a little more, especially if you skipped the wine).
Serve in bowls with extra olive oil drizzled on top. Store leftover pasta with sauce in the refrigerator for up to three days.
Since the juice in canned clams contains lots of sodium and preservatives, I drain and rinse the clams, and use bottled clam juice.