Soak the clams in cold water for a few hours, until they loose the sand; drain them and put them in a saucepan with 1/2 clove of garlic and the white wine and put them over the heat until they open.Remove the pan from the heat, remove the clams from the shell and place them into a bowl. Discard the clams that did not open, keeping a few aside for garnishing. Rinse the basil, once dried put it in a mixer with the leftover garlic, a pinch of salt, some oil and blast until it reaches a smooth cream; pour it in a bowl adding the leftover oil and the Parmesan.In the meanwhile toss the pasta in a pan with plenty of boiling salted water and drain it when al dente. Season it with the clams and pesto and a few spoonfuls of cooking liquid off the clams. Mix gently and serve immediately.