Prepare Coffee Liqueur: Dissolve Panella sugar in water, add to used coffee grounds along with discarded vanilla pods. Add vodka and stir to combine. Leave to infuse for up to two weeks.
Make Caramel: Bring milk up to temperature and add more coffee grounds for a richer flavor. Melt sugar and glucose until a rich deep golden color is achieved.
Combine Milk and Sugar: After passing the water-milk mixture through a chinois, gradually mix it into the melted sugar. Leave it to cool.
Finalize Caramel: Use a stick blender to incorporate butter and salt. Mix in the coffee liqueur and serve.