Preheat oven to 350 degrees F (175 degrees C). Line 12 muffin cups with paper muffin liners.
Whisk flour, green tea powder, baking powder, and salt together in a bowl. Beat sugar and oil together in another bowl; whisk in eggs and vanilla extract. Pour sugar mixture into flour mixture and stir gently until batter is just-combined. Stir applesauce into batter. Spoon batter into prepared muffin cups.
Bake in the preheated oven until a toothpick inserted into the center of a cupcake comes out clean, about 20 minutes. Cool in the pan for 10 minutes before removing to a wire rack to cool completely.