• Preheat your oven to 350°F (175°C). Grease and flour a bundt pan (10-cup or 12-cup) thoroughly, ensuring all surfaces are covered to prevent sticking.
• In a medium bowl, whisk together the flour, baking powder, baking soda, salt, cinnamon, ginger, nutmeg, and allspice. Set this aside.
• In a large mixing bowl, combine the melted butter, oil, and both sugars (dark brown and granulated). Whisk until well blended. Add the eggs one at a time, whisking well after each addition to ensure the mixture is smooth and evenly combined.
• Stir in the pumpkin puree and vanilla extract. Mix until smooth and fully incorporated.
• Gradually add the dry ingredients to the wet mixture, stirring gently after each addition until the batter is just combined. Be careful not to overmix, as this can make the cake dense.
• Pour the batter evenly into the prepared bundt pan. Bake for 50–60 minutes, or until a toothpick inserted into the center of the cake comes out clean.
• Allow the cake to cool in the pan for about 15 minutes, then carefully invert it onto a wire rack to cool completely.

For the Glaze

• In a small saucepan over low heat, combine the dulce de leche, butter, vanilla, and a pinch of salt. Stir continuously until the mixture is smooth and warmed through.
• Allow the glaze to cool enough to thicken to your desired consistency. You want it to be pourable but not so thin that it runs off the cake.
• Once the cake has fully cooled, drizzle the warm dulce de leche icing over the top. Allow it to set for a few minutes before serving.
• Slice the cake, serve, and enjoy the rich pumpkin flavor with the caramel-like icing on top.