I tried this with a variety of sparklers, including American hard cider (too beer-like), Martinelli's sparkling apple juice (quite sweet), and Prosecco (very good, but not French). I was hoping to keep it as French as possible and I liked it best with French sparkling cider. So my recommendation would be to go with one of them. (The Basque one I show in the post cost $9 in the U.S. so you don't need to break the bank on a bottle.)"Sweet" has become a bad word in the drinks world, and I'm not a fan of overly sweet drinks or cocktails either. So I prefer a brut, or dry variety of cider, as opposed to doux (sweet). The dash of lemon juice helps keep the balance in check, as does the extra cognac.