Gently rinse the zucchini flowers and pat them dry. Remove stamens from inside without tearing the petals.
In a small bowl, mix ricotta, Parmesan, egg, basil, salt, and pepper until creamy.
Carefully spoon the mixture into each flower, twisting the petals gently to seal.
Prepare a light batter by whisking flour with cold sparkling water until smooth.
Heat olive oil in a frying pan over medium-high heat. Dip each stuffed flower into the batter.
Fry until golden and crisp on both sides, about 2 to 3 minutes per side. Drain on paper towels.
Serve warm as a light appetizer or as part of a larger Italian spread.