In a medium skillet, heat the olive oil. Add the shallots and cook over moderate heat until softened, 3 minutes. Add the garlic and anchovies and cook over moderately low heat until fragrant, 4 minutes. Add the parsley and cook over moderate heat, tossing, until wilted, 2 minutes. Add the lemon juice and the butter and stir until melted. Remove the parsley from the heat and season with salt and pepper.