Preheat the oven to 300° F. In a large bowl, use a wooden spoon to stir butter and sugar together until creamy and smooth. Add the egg and extract and stir to combine. Add the flour, baking powder, and salt and stir to combine. Add the water and stir until smooth.
Transfer the mixture to a pastry bag fitted with a #7 plain round (3/8-inch) pastry tip. Pipe the batter onto two parchment-lined baking sheet in straight lines, about 6 inches long, at least 1/2 an inch apart. Bake until the sticks are set and light golden brown, 15 to 18 minutes, rotating the sheets halfway through. Let the sticks cool on the sheets on cooling racks for 5 minutes, then carefully transfer them to a rack to cool completely. Repeat with the remaining batter. Save the parchment-lined sheets for the next step.
Melt the chocolate in the microwave in a 2-cup glass measuring cup (or another microwave-safe, narrow vessel) in 15-second increments. One at time, carefully dip each stick in the melted chocolate. (Be careful. The sticks are somewhat fragile.) In order to get the chocolate up higher on the stick, tip the cup on its side and dip each stick in where the chocolate is the highest. Scrape off excess chocolate and lay each stick on the prepared sheets. Transfer the sheets to the refrigerator to set the chocolate. Store in an air-tight container in the freezer or fridge. (Alternatively, you can temper the chocolate so that the chocolate is hard at room temperature. For directions, see: http://food52.com/blog/3601-how-to-temper-chocolate)