Preheat oven to 350° F.
Grease three 4-inch springform pans and set aside.
Whisk together flour, spices, baking powder, and salt.
In a stand mixer, stir together baking soda, vinegar, tofu, vanilla, and pumpkin. Once combined, sift in dry ingredients until smooth. Pour a third of the batter into each of two of the prepared springform pans. Add the chocolate and cocoa powder to the remaining third, stir well,and pour into the third pan.
Bake for 25 minutes, until an inserted toothpick comes out clean. Cool completely on baking rack.
Zest an orange and set zest aside. Squeeze orange juice into bowl and stir in powdered sugar to reach a drizzling consistency.
Use a knife to level the three cakes. Stack them (use toothpicks to stabilize if necessary), drizzle icing between each layer, and pour any leftover icing on top. Finish with orange zest.