Wash the sage leaves thoroughly and pat them completely dry with paper towels. Leave the stems attached to make them easy to handle.
Prepare the batter: place the flour and a pinch of salt into a mixing bowl.
Create a well in the center of the flour and add the extra virgin olive oil. Begin stirring with a fork while gradually pouring in the ice-cold sparkling water, mixing quickly.
Finish mixing with a hand whisk until you achieve a smooth, uniform batter with no lumps.
Heat plenty of peanut oil in a deep, narrow saucepan. Check the temperature using a kitchen thermometer (the ideal temperature is 170°C / 340°F) or insert a wooden toothpick—when tiny bubbles immediately form around the wood, the oil is ready.
Hold each sage leaf by its stem and dip it into the batter to coat evenly.
Let any excess batter drip off gently, then drop the leaves into the hot oil. Fry for just a few minutes, turning as needed, until light golden and crisp.
Remove the fried sage with a slotted spoon and drain on paper towels. Season with a light sprinkle of salt if desired.
Serve immediately while still piping hot.
Frying Tip
Peanut oil is ideal for frying foods coated in this light batter because it has a high smoke point and maintains a steady, even temperature throughout cooking.