Preheat oven to 350 degrees F.: The oven needs to reach the correct heat so the cake sets and rises properly, producing an even crumb and a golden exterior. You should smell the faint warmth as the oven reaches temperature, and if you use an oven thermometer you will avoid underbaking. A common mistake is placing the pan in before the oven reaches full heat, which can cause the cake to bake unevenly; wait until the indicator shows ready and position the rack in the center for balanced browning.
Combine all ingredients in a mixing bowl and mix until well blended, approximately one minute with a hand mixer.: As you mix, notice the batter becoming smooth and uniform, with no streaks of dry mix. The aroma of cinnamon and pumpkin will lift, and the texture should be thick but pourable; if it is separated or oily, check that eggs and oil were added in the order suggested to help emulsify. Avoid overmixing, which can create a dense cake; stop as soon as the batter is homogeneous, and scrape the bowl so all pockets of mix are incorporated.
Pour batter into a bundt pan that has been generously sprayed with non-stick cooking spray.: When you pour, the batter should flow into the pan crevices, settling evenly. The sound is silent but the motion shows whether the pan was prepared well; a well greased pan prevents sticking and preserves the cake's shape. Use a spatula to even the top and tap the pan gently on the counter to release air bubbles. If the pan was not greased enough, the cake might stick and break when unmolding, so be thorough with the spray or butter and flour.
Bake for approximately 45 minutes, or until a toothpick inserted into cake comes out clean.: During baking you will notice a warm, spicy scent filling the kitchen and the top taking on an even golden tone. The toothpick test is the critical visual cue instead of relying solely on time, since ovens vary; the center should be set and not jiggly. Avoid opening the oven too often, which can cause the cake to sink; if the edges are browning too quickly while the center is raw, lower the oven slightly for the remaining time.
Remove from oven and allow to cool approximately 10 minutes prior to transferring cake to a plate or cake stand. Allow to cool an additional 20 minutes prior to frosting, if desired.: The cake will continue to set as it cools and you will feel a gentle change from warm to room temperature when touching the outside of the pan. Cooling briefly prevents the cake from breaking when unmolding, and the additional time before frosting avoids melting the frosting into the cake. A frequent error is removing the cake too soon, which leads to collapse or tearing; be patient and use a thin knife to loosen the edges if needed.
Combine ingredients and mix with a hand mixer until smooth and creamy. If desired more milk can be added to create a thinner frosting.: For the frosting, you will see a glossy, silky texture develop as the cream cheese and powdered sugar come together; the aroma will be sweet with a touch of tang from the cheese. Taste for balance and add a splash of milk to adjust consistency for spreading or drizzling. If the frosting is lumpy, it usually means the cream cheese was not fully softened; let it warm slightly at room temperature and rewhip to smooth it out.