In a kettle of boiling salted water boil the linguine until it is al dente, reserve 1/2 cup of the cooking water, and drain the linguine well.

While the linguine is cooking, in a heavy skillet cook the butter over moderate heat, swirling the skillet occasionally, until it is nut-brown in color. In a large bowl whisk together the butter, the parsley, the Parmesan, and the oregano until the mixture is combined well and whisk in the yogurt and salt and pepper to taste. Add the linguine, toss the mixture well, and add enough of the reserved cooking water to thin the sauce to the desired consistency.