In large pot of boiling salted water, add linguine, then cook until al dente, according to box instructions, reserving 1 cup of linguine water for sauce.

In large frying pan over high heat, add olive oil, butter, and clams, then toss. Add garlic and shallots (or onions), stirring until mixture is slightly brown and clams are open, about 3 minutes. Add flour and toss to coat. Add white wine, lemon juice, and linguine water, stirring to thicken sauce. Remove from heat; set aside.

Place pasta in four bowls, then cover with clams and sauce in equal portions. Sprinkle parsley over bowls and serve.