Preheat the oven to 350F(180C).
Zest the lemons and squeeze the juice. Don't forget to remove the seeds.
Mix the sour cream with the lemon zest and juice. Set aside.
Sift the flour and mix in the baking soda, baking powder, and salt. Set aside.
In a stand mixer with the paddle attachment or hand mixer at medium speed, beat the soft butter and sugar until light and fluffy. Add the eggs one at a time as you stop and scrape the sides of the bowl after each one. Add the sour cream mixture. When all is mixed, gradually add the flour. Mix at low to medium speed for a few seconds until the flour is incorporated, or finish by hand. Don't overmix the batter. Grease the pan with butter and sprinkle flour. I like to use a sieve to cover every part of the pan. Tap off any excess flour.
Transfer the batter to the pan, spread it evenly, and bake on the middle rack for 30-35 minutes (fan on) or until a toothpick comes out clean or with a few crumbs, but not wet.
When ready, take it out from the oven and let it cool for 5 minutes. Then flip it over and let it cool for another 5 minutes. The cake might fall off the pan on its own, or you might need to give it a little help. Using a rubber spatula, separate the edges from the pan if they are stuck and give it a little shake until it comes off.
Make the lemon syrup by combining the sugar, lemon juice, and water. Cook until it starts boiling and the sugar has dissolved. Set aside.
Once the cake is flipped and out of the pan, spread the lemon syrup all over it using a kitchen brush.
Make the glaze by mixing the powdered sugar, melted butter, and lemon juice. Drizzle over the cooled cake. Enjoy!