Prepare your fries in whichever method you prefer. I have a deep fryer so I double fry them (10mins at 150C/300F, a further 5 minutes at 190C/375F). You could also oven bake them or air fry them if you like.
In a small saucepan, bring the white wine and garlic to a boil. Mix the grated gruyere and flour together and then add it in too. Finally add the kirsch (if using) and whisk constantly until the cheese has melted and is bubbly.
You know what to do! Dump the fries on a plate, pour the sauce in, and grab a fork.