Preheat oven to 350 F. Spray a 9-inch springform pan with floured cooking spray or grease and flour the pan; set aside. Don’t use a regular 9-inch round cake pan because it’s not deep enough and the cake will overflow.: You should feel the warmth of the oven filling the space and notice a steady, even heat when you open the door, which is crucial for even rising. The springform pan creates higher walls so the batter has room; you may hear slight creaks as metal warms in the oven. I place the pan on a baking sheet as insurance against leaks, a tip learned after one messy bake. If the pan is not properly greased and floured, the cake can stick and tear when unmolding, so take the extra minute to do this step carefully.
To a large bowl, add the eggs, pumpkin, sugars, oil, pumpkin pie spice, vanilla, cinnamon, cloves, and whisk to combine.: You will notice the batter darken and the aromas of spice blooming as you whisk, with the glossy sheen from the oil binding the mixture. This step begins flavor marriage; whisking ensures the eggs are evenly distributed which gives a consistent crumb. A common pitfall is under-whisking, leaving streaks of dry sugar or inconsistent texture. Use a whisk or a mixer on low for uniformity, but avoid overbeating which would incorporate too much air and change the cake's density.
Add the carrots and stir to combine.: As you fold in the grated carrots , you will see orange flecks throughout the batter and feel a slight resistance from the vegetable fibers. The carrots contribute moisture and tiny bursts of texture, and they help keep the cake tender. Over-stirring at this stage can break down the carrots too much and create a pasty texture, so use a gentle folding motion until just dispersed.
Add the flour, baking powder, baking soda, salt, and stir until just combined, don’t overmix.: The dry ingredients will take the batter from glossy to slightly thicker, and you should mix until you no longer see streaks of flour. This is where you watch the texture change under your spatula, and a few small lumps are fine. The why is simple, gluten forms as you mix, so overmixing will make the cake tough. If you overwork the batter, the crumb becomes dense rather than tender, so stop as soon as cohesion is achieved.
Optionally add the raisins and/or nuts and stir to combine. Turn batter out into prepared pan, smoothing the top lightly with a spatula. Bake for about 45 minutes or until center is set and a toothpick inserted in the center comes out clean or with a few moist crumbs, no batter. In the last 10 minutes, loosely drape a sheet of foil over the top of the springform pan to prevent the top from becoming overly browned.: When you fold in raisins or nuts they will distribute pockets of texture that punctuate each bite. Spread the batter evenly so the cake rises uniformly, and gently smooth the top for an attractive finish. During baking you will smell the spices deepen and see the edges pull away slightly from the pan, a sign of doneness. If you skip the foil in the final minutes, the top may brown too quickly; conversely, too much foil early can slow browning entirely. A toothpick with a few moist crumbs is the ideal result, indicating a moist but fully baked interior.
To a large bowl (or to the bowl of a stand mixer using the paddle attachment) add the cream cheese, butter, and beat with an electric mixer on high-speed until fluffy, about 2 minutes.: The mixture should become pale and airy, with a light, billowy texture and a faint, sweet dairy scent. Beating on high introduces air that makes the frosting spreadable and smooth. If the cream cheese or butter are too cold you will feel resistance and see lumps, so ensure they are softened to room temperature. Overheating while trying to speed things up can make the mixture runny, so keep pulses controlled.
Add the confectioners’ sugar, vanilla, salt, and beat until smooth and incorporated, about 2 minutes.: The frosting will transition from a soft mound to a silky ribbon that holds its shape when lifted with a spatula, and it should feel creamy and not grainy. The confectioners’ sugar dissolves into the dairy creating that signature smooth mouthfeel. If you add the sugar too quickly you might get a cloud of sugar dust, and if you overbeat, the frosting can be too airy and unstable for spreading. Taste and adjust salt to balance the sweetness.
Turn frosting out onto cake and spread into a smooth, even, flat layer using a spatula or knife. Unlatch springform pan, slice, and serve.: Spreading the frosting should feel like a final flourish, leaving a satiny surface that gleams faintly under light. As you spread, small peaks will relax into a smooth finish if your spatula is warm; dip it briefly in hot water and dry for an ultra-sleek top. If the cake is still warm the frosting will sag and melt, so the key is patience and a completely cooled cake. When slicing, a sharp knife with clean wipes between cuts keeps slices neat and presentable.