Preheat the oven to 350 degrees and generously spray a bundt pan with non-stick cooking spray.
In the bowl of a stand-up mixer with the paddle attachment, combine the cake mix, eggs, whole milk, flour, pumpkin puree, and vanilla extract. Mix on low speed for 1 minute, then increase to medium speed for an additional 2 minutes. Scrape down the sides of the bowl with a spatula to ensure even mixing.
Pour the batter into the prepared bundt pan, spreading it out evenly.
Bake in the preheated oven for 40-50 minutes or until a toothpick inserted into the center comes out clean.
Allow the cake to cool on a wire rack for 20 minutes before flipping it out onto a serving tray. Continue to cool for an additional 1 hour.
Cream Cheese Frosting:
In the mixer bowl with the paddle attachment, beat the cream cheese on medium speed for 3-4 minutes.
Add the butter and vanilla extract and continue to mix for another 2-3 minutes.
Gradually add the powdered sugar, one cup at a time, mixing until fully incorporated. Taste the frosting after each addition and adjust for desired thickness.
Add milk, ½ teaspoon at a time, to thin out the frosting to your liking.
Drizzling the Frosting:
Place two cups of cream cheese frosting in a microwave-safe bowl. Heat in 5-second increments until the frosting is slightly runny.
Drizzle the runny frosting over the cooled cake, starting from the inside and making a back-and-forth motion. Repeat this process around the entire cake three times.
Slice and enjoy your delicious Pumpkin Spice Bundt Cake with Cream Cheese Frosting!