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 - In a large bowl, beat butter, oil, and dark brown sugar until light and fluffy, approximately 3 minutes.
04 - Add molasses to the creamed mixture and mix until fully combined.
05 - Add eggs individually, beating well after each addition. Stir in vanilla extract.
06 - Add half of the dry ingredient blend to the wet mixture; mix on low speed until just combined.
07 - Pour in buttermilk and mix gently. Add remaining dry mixture and blend until smooth without overmixing.
08 - Pour batter evenly into prepared Bundt pan and smooth the surface. Bake 40 to 50 minutes or until a skewer inserted in center comes out clean.
09 - Allow cake to cool in pan for 15 minutes, then invert onto a wire rack to cool completely.
10 - Whisk powdered sugar, milk, and vanilla extract until smooth and slightly thick but pourable; add more milk if needed.
11 - Drizzle glaze over cooled cake, letting it run down sides. Allow glaze to set prior to slicing and serving.