Add the crushed tomatoes and whole peeled tomatoes and turn the heat to medium-high. Once the sauce begins to bubble, turn the heat to low. Add the basil sprigs and sugar, if using. Season to taste with salt and pepper. Simmer for 30 minutes, uncovered, stirring occasionally, until the sauce is thickened and the flavors have melted. Add water, as necessary, to loosen up the sauce if it sticks.