Line a coffee cup with a paper coffee filter. Add coffee grounds into the filter. Bring water to a boil in a sauce pan and remove 1/4 cup of the boiling water. Pour 1/4 cup of boiling water over the coffee grounds. Let steep for a few minutes and cool down slightly.

While the coffee is cooling, . in a sauce pan over medium-high heat, whisk together sugar and remaining water – bringing to a rapid boil. Cover and let boil for 5-8 minutes, or until the mixture starts to turn amber/golden brown and you can smell the caramelization happening.

While this is simmering, remove coffee filter from the mug and let drain as much coffee extract as possibly. Gently squeeze the filter to make sure you have got as much as you can out of it. Discard the filter.
Uncover the pan and working carefully – slowly stream in the whipping cream while whisking the mixture vigorously. The mixture will bubble and foam very quickly, so whisk constantly. Whisk until the foaming subsides. Stir in the vanilla, and the coffee extract, and finally the salt. Bring mixture back to a boil to thicken.
Remove from the heat and allow to cool completely before consuming.