Combine the cream and 1/4 cup condensed milk. Divide the mixture among the molds. Freeze until almost solid, about 1 hour.
Meanwhile, in a bowl, whisk together the espresso, 2 tsp. cocoa powder and the remaining 1/4 cup condensed milk; refrigerate until cold.
Divide the mixture among the molds. Insert the ice-pop sticks, piercing the cream layer; freeze until solid, about 4 hours. Run warm water over the molds to remove the pops; dust the cream layer with more cocoa powder.