Cut one garlic clove in half and rub the cut halves over the inside of the fondue pot. Finely chop the remaining garlic clove, then add to the pan.
Add the grated havarti,Fontina and Gouda to the pan along with the cornflour, if using (see Know-how), and a good grating of nutmeg and black pepper. Stir everything together using a wooden spoon.
Pour in the wine, then set the pan over a medium heat. Gently heat, stirring, taking care not to overheat the mixture. Once the cheese has melted, turn up the heat slightly and let the mixture just come to a gentle simmer. Cook for a few minutes to thicken.
Remove the pan from the heat, stir in the kirsch and season to taste. Transfer the pan to the center of the table, setting it on the fondue stand or a heatproof trivet with the serving accompaniments (see below), then let everyone dive in.