Put nonfat milk powder in a measuring cup; stir in enough black tea to make 1 cup. Stir until milk is dissolved. Set aside to cool.

Preheat oven to 375 degrees F (190 degrees C). Spray a muffin pan with nonstick cooking spray.

Combine cinnamon, nutmeg, allspice, cloves, and black pepper together in a small bowl.

Sift spice mixture, flour, brown sugar, cocoa powder, baking soda, baking powder, and salt together into a large bowl. Stir cooled tea mixture, oil, and egg into flour mixture until batter is just combined; fold in ginger. Spoon batter into the prepared muffin cups, filling each 3/4-full.

Bake in the preheated oven until a toothpick inserted in the center of a cupcake comes out clean, 12 to 15 minutes. Cool cupcakes on wire racks.