Cook basil: Heat a medium saucepan over medium heat. Sauté chopped ½ cup fresh basil in 1 tablespoon butter until fragrant, about one minute.
Heat diluted sauce: Add the entire jar (roughly 24 ounces) of pasta sauce and the 2 cups water. Increase heat to medium-high and cook until heated through, about 5-7 minutes.
Stir in cream: Remove the pan from the heat and stir in the ½ cup heavy cream. To serve, top with fresh basil and freshly ground pepper, if desired.
