Line an 8" x 8" pan with foil and grease the foil well.
Place a 1/2 cup of the cream in a medium saucepan. Add the espresso powder, corn syrup, salt and sugar. Cook the mixture over medium heat; stir until the espresso powder and sugar are dissolved and it starts to boil. Cover the pan and let it boil for about 3 minutes. Then uncover the pan, and check the temperature. It should be at 235°F. to 240°F. If it is, take the pan off the heat and add the vanilla. If it isn't, allow the mixture to boil for 1 - 2 minutes more. Take the pan off the heat and set it aside to cool.
Pour the remaining 1/2 cup of cream into another saucepan. Heat it until it's just beginning to steam. Remove from the heat, and add the white chocolate. Let the mixture sit, untouched, for about 5 minutes to melt the chocolate. Once the chocolate has melted, vigorously whisk the mixture until it is shiny and smooth.
Add the sugar mixture to the chocolate mixture; stir to combine. Pour into the prepared pan. Sprinkle with cocoa. Refrigerate to set up. Remove from the pan and turn over; sprinkle with the remaining cocoa. Cut into 1-inch cubes. Stack 2 to 3 on each wooden stick.