How to Make It
Put orange in a 1-pt. glass measuring cup and add water to make 1 cup. Cover loosely with plastic wrap and microwave until orange is soft, 4 minutes. Drain.
Whirl orange in a food processor until finely chopped. Let cool. Add all-purpose flour, almond flour, granulated sugar, butter, baking powder, salt, and egg; pulse until blended. Pour batter into a 1 1/4- to 1 1/2-cup microwave-safe mug. Stir in chocolate chips.
Microwave until a toothpick inserted in center comes out barely clean, about 2 minutes (cake rises above mug, then sinks down as it cools). Let cool 20 minutes. Sprinkle with powdered sugar.
*Find with baking supplies.