Heat oven to 325 degrees and thoroughly grease a 10-cup bundt pan, making sure to get the center core. Sprinkle granulated sugar over the bottom of the pan and shake the sugar all around to coat the bottom, sides, and center core. See notes below for full instructions.
Using a citrus zester, zest four lemons over a piece of parchment paper or wax paper.
Combine the sugar and lemon zest in a small bowl and mix with your fingers until the sugar becomes moist and grainy.
Remove the peel from the lemons you just zested by cutting an end off the lemon and setting it on a cutting then cut the pith off the lemon by slicing it off with a knife.
Now you have a lemon with no peel or pith on it. Hold the lemon over a medium-sized bowl cutting each segment on either side of the membrane to remove the flesh using a paring knife. This is called supreming. When done make sure to remove any seeds and break up the lemon segments in the juice. Do this for each lemon.
In a large mixing bowl, or the bowl of a stand mixer, beat the butter and half of the sugar mixture for two minutes and medium speed with the mixer. Add the remaining sugar mixture and beat for four minutes. Make sure to scrape the bowl occasionally.
Add the eggs to the above mixture one at a time, beating each just until combined.
On the lowest mixer setting, mix in the dry ingredients: flour, baking soda, and salt. Scrape the bowl after mixing.
Mix in the sour cream on low speed until just combined.
With a rubber spatula, fold in the lemon segments and all the juice in the bowl.
Pour the batter into your prepared pan. Bake about 1 ¼ to 1 ½ hours until a cake tester at the center of the cake comes out clean. Let cool for 15 minutes then turn out onto a cooling rack.See notes below on depanning a bundt cake.