Preheat your oven to 350°F (180°C). Butter a 9-inch round cake pan and dust it with flour, tapping out the excess.
In a large bowl, whisk together the canned pumpkin puree, granulated sugar, vegetable oil, and eggs until the mixture is smooth.
In another bowl, whisk together 2 cups all-purpose flour, 4 teaspoons baking powder, 1 teaspoon ground cinnamon, 1/2 teaspoon ground nutmeg, and a pinch of salt.
Gradually add the dry ingredients to the wet ingredients, stirring with a spatula until just combined and smooth.
Pour the batter into the prepared pan and bake for 40 to 50 minutes, or until a toothpick inserted into the center comes out clean.
Let the cake cool in the pan for 10 minutes, then invert it onto a wire rack and let it cool completely.