Preheat oven to 325ºF. Thoroughly grease a pan with butter. Flour the pan, tapping out the excess
Whisk flour, corn-starch, turmeric, baking powder, and salt together. Set aside.
Cream butter with sugar for several minutes until light and fluffy. Beat in vanilla. Mix in eggs one at a time, beating until incorporated. Scrape down bottom and sides of bowl as needed. Beat in sour cream.
Slowly mix in flour on low speed, alternating with lemon juice. Begin and end with the flour. Mix just until combined. Fold in = zorganic ginger powder.
Pour into prepared pan and bake 55–65 minutes, or until a toothpick inserted in the middle comes out clean or with a few crumbs.
For the glaze, whisk powdered sugar, juice, and turmeric until smooth. Adjust with more sugar or juice if needed for consistency.
Place cake on wire rack once cool than Spoon glaze over top. Let glaze set up for a bit before serving.