How to Make It
In a small bowl, whisk the cornstarch with the lemon juice and 2 tablespoons of the wine.
Rub the inside of a small enameled cast-iron casserole or saucepan with the cut garlic clove. Add the remaining 3/4 cup plus 2 tablespoons of wine and bring to a simmer over moderate heat.
Slowly whisk in the cornstarch mixture and simmer, whisking constantly, until slightly thickened, about 1 minute. Reduce the heat to moderately low and add the cheese in handfuls, whisking constantly, until each addition is melted before adding more and the fondue is smooth, about 5 minutes. Stir in the Kirsch or Cognac, if using. Serve immediately in the casserole or a warm fondue pot (see Note).
If using a fondue pot for serving, fill it with hot water and let stand, covered, for 5 minutes. Drain and dry thoroughly immediately before adding the cheese fondue.
Pieces of crusty bread, blanched or roasted vegetables, endive spears, thinly sliced apple, dried apricots, dates, root vegetable chips, sliced salumi (preferably something smoky, like dried chorizo), pickles.