01 - Preheat oven to 350°F and 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, ground ginger, cinnamon, cloves, nutmeg, and allspice; set aside.
03 - In a large bowl, beat softened butter, oil, and brown sugar until light and fluffy, approximately 3 minutes.
04 - Add molasses to the creamed mixture and blend until fully combined.
05 - Beat in eggs one at a time, mixing well after each addition, then stir in vanilla extract.
06 - Add half of the flour mixture to wet ingredients and mix on low speed just until incorporated.
07 - Gently pour in buttermilk, mix lightly, then add remaining flour mixture; stir until batter is smooth without overmixing.
08 - Pour batter evenly into prepared Bundt pan and smooth surface.
09 - Bake for 40 to 50 minutes or until a toothpick inserted into center comes out clean.
10 - Allow cake to cool in pan for 15 minutes before inverting onto a wire rack to cool completely.
11 - Whisk together powdered sugar, milk, and vanilla extract until smooth and pourable; adjust milk quantity as needed.
12 - Drizzle glaze evenly over cooled cake, letting it drip down sides; allow glaze to set before serving.