Prosecco, Cava, and Champagne are all made by the same method.
With Cava and Champagne, bubbles are the result of a second fermentation that takes place inside each bottle. Virtually all Prosecco (basic and Conegliano Valdobbiadene Prosecco Superiore) are made by the Charmat process whereby the second bubble-inducing fermentation takes place inside tanks. (This process is sometimes called “Charmat-Martinotti” since it was first developed in 1895 by Italy’s Federico Martinotti and a decade later, adapted and modified by the Frenchman Eugène Charmat). The result is a bright, fruit-forward, fresh-tasting sparkler that minimizes yeasty flavors. That said, a small number of Prosecco Superiore producers have returned to an ancient method called Col Fondo, whereby the second fermentation takes place in bottles but the yeasts are never removed. Kind of like the Prosecco version of Pétillant Naturel.