Combine milk, 2 tablespoons butter, salt and pepper in a heavy saucepan and bring to a full boil over medium-high heat. Remove from heat. Add flour all at once, stirring constantly. Return pan to medium heat and cook, stirring constantly until dough pulls away from sides of pan and a thin film covers the bottom, 4 to 5 minutes. Remove pan from heat and add eggs, one at a time, beating vigorously and constantly until dough is smooth. Add ricotta and basil. Mix well. Spread remaining 1/2 teaspoon butter in a shallow baking dish. Bring a large pot of salted water to a simmer. Ease 1 teaspoon of dough at a time into water, being careful not to crowd the gnocchi, and simmer--do not boil--uncovered, until light and fluffy, about 20 to 25 minutes. Remove with slotted spoon and drain on paper towels. When all gnocchi are cooked, place in baking dish, cover gnocchi with sauce and sprinkle with Parmesan cheese. Broil just until cheese is browned and bubbling.