How to Make It
In a medium saucepan, combine the espresso powder with the brown sugar and 1 cup of hot water and bring to a simmer. Add the dates and simmer until softened, about 5 minutes. Using a slotted spoon, transfer the dates to a plate to cool. Peel the dates and discard the skins. Coarsely chop the dates, adding 2 tablespoons of their syrup to loosen them slightly. Spoon the date mixture onto a sheet of plastic wrap and roll into a 6-inch log. Roll up the log and twist the ends to seal. Freeze until firm, at least 4 hours or overnight.
Unwrap the log and cut into 12 slices; transfer to plates. Top each slice with a dollop of yogurt, sprinkle with the pistachios and serve.