Line an 8x8 pan with parchment paper, leaving an overhang on two sides, then spray lightly with non-stick cooking spray. Set aside.
Combine butter, sugar, cream, corn syrup and salt in large deep pot.
Bring to a boil over medium-high heat, uncovered, stirring often and scraping the sides of the pan to incorporate all the sugar.
Once mixture starts to boil, insert the thermometer.
Reduce the heat to medium-low, and cook uncovered, stirring occasionally until the mixtures reaches 246 degrees F.
While the caramel is cooking, in a small bowl, combine the espresso powder, one teaspoon hot water and the vanilla extract.
When mixture reaches 246 degrees, remove it from the heat and stir in the espresso powder mixture until smooth and well combined.
Pour into prepared pan.
Let stand at room temperature at least 8 hours, but preferably overnight.
Cut into one inch pieces and individually wrap in cellophane or wax paper.