Prosecco is Italian sparkling wine (typically made from the Glera grape) produced most often by the tank (Charmat) method. That method tends to preserve fresh fruit aromatics rather than developing heavy yeasty notes.
Flavor is commonly pear, apple, white flower, and light citrus with softer bready character than Champagne. Compared with Champagne, it’s usually less toasty and sometimes slightly softer in acidity, depending on the bottle.