Start by rubbing the inside of your pot with the garlic clove cut in half. Then add the wine and lemon juice to the pot and heat to a simmer over a medium heat.
Coat the grated cheese with the cornstarch by shaking in a sealed zip bag.
Slowly add the cheese to the wine mixture, handful by handful, stirring in a figure eight pattern to incorporate it each time until it's all mixed, creamy and smooth.
Add in the brandy, dry mustard and nutmeg and stir to combine.