In a heavy, medium saucepan melt the butter over low heat. Add the garlic and then the flour and stir to combine. Cook, stirring constantly, for 3 minutes. Increase the heat to medium and whisk in the half-and-half little by little. Cook until thickened, about 4 to 5 minutes, stirring frequently. Remove from the heat; add 2 cups of the grated Parmesan. Season with the salt, pepper and stir until cheese is melted and sauce is smooth. Cover and set aside.