Melt the butter in a small pan over a medium to low heat until liquid.
Whisk sugar, coffee and cream into the melted butter, making sure the coffee is fully dissolved.
Gently bring to the boil whisking the whole time.
Reduce the heat and continue to whisk for another 2-3 minutes to allow the sauce to thicken a little.
Remove from the heat and add in the vanilla paste.
Drizzle the syrup over French Toast if serving immediately.
Tip: You can also make the syrup before the toast and store in the fridge. If you do this, make sure to gently reheat when ready to use as it will solidify in the fridge.