Prepare the fondue pot by rubbing the inside with the halved garlic clove. This infuses a subtle garlic flavor into the cheese mixture. Discard the garlic clove afterward.

In a small bowl, whisk together the cornstarch and lemon juice until smooth. This mixture will help to thicken the fondue and prevent it from becoming oily.

Pour the white wine into a medium saucepan or the fondue pot if it's stovetop safe. Heat the wine over medium-low heat until it is warm but not boiling. You should see a slight steam rising from the surface.

Gradually add the shredded Gruyère and Emmental cheeses to the warm wine, a handful at a time. Stir continuously with a wooden spoon or whisk in a figure-eight motion. Allow each addition of cheese to melt almost completely before adding more. This gradual addition and constant stirring is crucial for a smooth, creamy fondue.

Once all the cheese has melted and the mixture is smooth and creamy, slowly stir in the cornstarch and lemon juice mixture. Continue to stir until the fondue thickens slightly, which should take about 1-2 minutes.

Stir in the kirsch, freshly ground black pepper, and a pinch of nutmeg (if using). Continue to stir until well combined. The kirsch adds a traditional depth of flavor and helps emulsify the fondue.

If using a stovetop fondue pot, transfer the cheese mixture into the fondue pot. If you cooked directly in a fondue pot, ensure it is placed over its heat source (like a burner or small flame) on a low setting to keep the fondue warm and melted, but not simmering.

Arrange the cubed crusty bread and prepared vegetables and potatoes on a platter around the fondue pot. Ensure each guest has fondue forks or long skewers.

Instruct guests to spear a piece of bread or vegetable onto their fondue fork and swirl it gently in the melted cheese until coated. Enjoy immediately.