Sweet matcha, Japanese green tea that has been ground into a fine powder and combined with sugar, sets these biscotti-like cookies apart.
Preheat oven to 325 degrees. Whisk to combine flour, baking powder, and salt in a bowl. In a separate bowl, whisk egg, matcha, and vanilla until smooth. Slowly pour oil into egg mixture, whisking constantly until incorporated. Add flour mixture and stir until smooth; mix in almonds and ginger. Chill 30 minutes.
Divide dough into thirds, and shape each into a log, 1 1/2 inches wide by 6 inches long. Place on a parchment-lined baking sheet, spacing 3 inches apart. Bake, rotating sheet halfway through, until center is firm and bottom edges are slightly golden, 18 to 20 minutes. Remove from oven and sprinkle about 1 tablespoon sugar evenly over logs. Let cool on sheet 15 minutes, then cut into 1/2-inch-thick slices using a serrated knife.
Arrange slices on parchment-lined baking sheet, cut side down, and sprinkle evenly with about 2 teaspoons more sugar. Bake until firm in center, 6 to 8 minutes. Let cookies cool on baking sheet on a wire rack, 5 minutes. Flip cookies, and sprinkle evenly with about 2 teaspoons more sugar. Return to oven, and bake until slightly browned on edges, about 6 minutes more. Let cool completely on sheet on a wire rack. Cookies can be stored in an airtight container at room temperature up to 2 weeks.
Matcha is carried at many specialty food stores and some supermarkets. If you can't find sweet matcha, combine 1/3 cup sugar with 2 tablespoons regular matcha or finely ground green tea leaves.