Preheat your oven to 350°F (175°C) and lightly grease a 9×9 inch baking pan with cooking spray or butter.
In a large mixing bowl, combine the pumpkin puree, vegetable oil, and granulated sugar. Beat in the eggs until fully incorporated.
To the same bowl, add the flour, baking soda, cinnamon, nutmeg, and salt. Stir until just combined; do not overmix.
Transfer the batter into the prepared baking pan, smoothing the top with a spatula.
Bake for about 25-30 minutes, or until a toothpick inserted into the center comes out clean.
Allow the cake to cool in the pan for about 10 minutes, then transfer to a wire rack to cool completely.
Enjoy your One Bowl Pumpkin Spice Coffee Cake plain or top it with whipped cream or a simple glaze for added sweetness.