Special equipment: a 10-inch Bundt pan
For the spice cake: Preheat the oven to 350 degrees F. Spray the inside of a 10-inch Bundt pan with cooking spray.
Cream the butter, granulated sugar and brown sugar with an electric mixer on medium speed until light and fluffy.
Sift together the flour, baking soda, cinnamon, cloves and nutmeg.
Add the eggs to the creamed butter, one at a time, beating after each addition. Add the sour cream, alternating with the flour mixture, beginning and ending with the flour and beating until no flour is visible -- don't overbeat.
Pour the batter into the prepared pan; tap the pan on the counter to remove any air pockets. Bake for 1 hour, until a toothpick inserted into the center of the cake comes out clean. Cool slightly in the pan, 5 to 10 minutes, then turn out onto a rack while still warm.
For the lemon sauce: Meanwhile, whisk together the eggs and granulated sugar in the top of a double boiler over medium heat. Stir in the lemon juice, zest and butter. Cook until thickened, whisking often, about 30 minutes.
Serve the cake warm or room temperature with the lemon sauce.