Preheat your oven to 350°F (175°C).
Grease and flour a 9x13 inch baking pan.
In a mixing bowl, cream together the butter, granulated sugar, and brown sugar until fluffy.
Add the eggs one at a time, mixing well after each addition.
Stir in the pumpkin puree and vanilla extract.
In a separate bowl, whisk together the flour, baking powder, baking soda, salt, and spices.
Gradually add the dry ingredients to the wet mixture, alternating with milk.
Pour the batter into the prepared pan and smooth the top.
Bake for 30-35 minutes or until a toothpick inserted in the center comes out clean.
Allow the cake to cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.
While the cake cools, prepare the frosting by whisking together powdered sugar and milk.
Drizzle the frosting over the cooled cake before serving.
