01 - Preheat oven to 350°F. Grease and line a 9x9-inch baking pan with parchment paper, leaving an overhang for easy removal.
02 - Whisk together flour, baking powder, baking soda, salt, ground ginger, cinnamon, and nutmeg in a medium bowl.
03 - In a large bowl, beat granulated sugar, brown sugar, and vegetable oil until smooth. Add eggs one at a time, mixing well after each addition.
04 - Blend pumpkin purée, fresh ginger, lemon zest, lemon juice, and vanilla extract into the wet mixture until homogenous.
05 - Gradually fold dry ingredients into wet ingredients until just combined. Avoid overmixing to maintain cake tenderness.
06 - Pour batter into the prepared pan and smooth the surface with a spatula.
07 - Bake for 32 to 36 minutes, or until a toothpick inserted in the center comes out clean.
08 - Allow the cake to cool entirely in the pan on a wire rack.
09 - Whisk together powdered sugar, 2 to 3 tablespoons lemon juice, and lemon zest until a smooth, pourable glaze is formed.
10 - Drizzle glaze evenly over cooled cake. Once the glaze sets, lift cake from the pan using parchment paper overhang and cut into 16 squares.