01 - Preheat oven to 350°F. Thoroughly grease and flour a 10 to 12-cup Bundt pan, tapping out excess flour.
02 - In a medium bowl, whisk together flour, baking powder, baking soda, salt, ginger, cinnamon, cloves, nutmeg, and allspice. Set aside.
03 - Beat butter, oil, and brown sugar in a large bowl until light and fluffy, approximately 3 minutes.
04 - Add molasses to the creamed mixture and blend thoroughly.
05 - Add eggs one at a time, beating well after each addition, then mix in vanilla extract.
06 - Add half of the flour mixture to the wet ingredients; mix on low speed until just combined.
07 - Pour in buttermilk and mix gently. Add remaining flour mixture and blend until smooth without overmixing.
08 - Pour batter evenly into prepared Bundt pan and smooth the surface.
09 - Bake for 40 to 50 minutes until a toothpick inserted into the center comes out clean.
10 - Allow the cake to cool in the pan for 15 minutes, then invert onto a wire rack and cool completely.
11 - Whisk together powdered sugar, milk, and vanilla extract until smooth and slightly thick but pourable. Adjust milk quantity as needed.
12 - Drizzle glaze over cooled cake; allow it to set before slicing and serving.