In a blender, combine the cream, milk, sweetener, collagen, and 1 teaspoon of the espresso powder. Blend until smooth, and adjust espresso powder to taste1. Pour into popsicle molds and place in the freezer for 1 ½ to 2 hours.
Remove from freezer and press wooden sticks about ⅔ down into the popsicles and place back into the freezer until solid, another 4 to 6 hours.
In a heatproof bowl set over a pan of barely simmering water, combine the white chocolate and the cocoa butter. Stir until smooth. Do not walk away, as white chocolate can get overheated and seize very easily.
Working with one popsicle at a time, dip the ends into the white chocolate and set on a waxed paper lined tray in the freezer to set.
Notes about collagen: You can use plain collagen instead of the salted caramel, and add some vanilla extract or caramel extract (about ½ tsp). You can also skip the collagen altogether, although I do recommend it as it improves the consistency of the popsicles.