I love Federweisser and Zwiebelkuchen -- perfect combination. But if you want a home version, try this. Welch's white grape juice in the plastic jug -- 64 ounces -- add 3/4 cup of sugar, sprinkle in a little yeast (1/4 tsp or so). Put a bung and an air lock and leave it on the counter. It will start fermenting and the bubbles will come faster and faster. When they start slowing down, put the whole thing in the refrigerator to mostly halt the fermentation. Drink within a day or two. Half fermented, sweet, bubbly, mildly alcoholic, a fun party beverage. It's not Federweisser for sure, but it's maybe Federweisser-adjacent.