Prepare the pan: Coat the inside of the loaf pan with a thin layer of butter, dust with all-purpose flour, and tap the pan to remove the excess. Chill it in the fridge until ready to use.By chilling the prepared pan until right before use, the coating won't get scratched or slide when you pour the batter. This helps create a more beautiful, even caramelization on the surface of the cake.Also finish other preparations: Preheat the oven to 325ºF (163ºC). Leave the butter at room temperature to soften beforehand. Sift the all-purpose flour and baking powder together.

Mix sugar, salt, and lemon zest: Zest lemons directly into the bowl of a stand mixer. Mix the zest with the granulated sugar and salt.I like to do this step first and let it sit while I weigh the other ingredients. This allows the aromatic oils to fully infuse into the sugar.

Add softened butter and whip: Add the softened butter to the sugar mixture and whip. Scrape the bottom and sides of the bowl with a rubber spatula to incorporate any butter attached to the sides. Continue whipping until the mixture is very fluffy and pale.

Add eggs and whip: Warm the eggs until they are slightly warm to the touch (ideally 90ºF | 32ºC). Add eggs very gradually (I divided them into eight additions) and whip well before adding the next. Scrape the bowl periodically to ensure it's blended evenly.Eggs blend with butter more easily when they are not cold. Use a water bath or microwave to take the chill off. If using a microwave, check every 5-10 seconds to prevent the eggs from cooking. Be careful not to over-warm them, or the butter will melt.

Add sifted flour: Add the sifted flour and baking powder. Mix well with a rubber spatula just until no flour remains. Scrape the bottom and sides to ensure no pockets of flour are hiding.

Add remaining wet ingredients: Add the sour cream, honey, vanilla extract, and lemon juice. Mix with a spatula until everything is evenly incorporated.

Bake the cake: Scoop the batter into the prepared pan. Optional: Score the center of the surface with a line of melted butter using a dough scraper or spatula. This helps the cake crack down the middle as it rises, creating an elegant look. Bake at 325ºF (163ºC) for 60-75 minutes. To check if it's done, insert a toothpick into the center; it should come out clean with just a few crumbs. Let the cake rest for 5-10 minutes before removing it from the pan.The cake is very soft right after baking. Don't remove it from the pan immediately; wait about ten minutes. Meanwhile, let's prepare the lemon syrup!

Apply lemon syrup: Heat water, lemon juice, and sugar in a small saucepan until it boils. Take the hot cake out of the pan carefully and apply the syrup all over the surface with a pastry brush. Ensure the cake cools completely before glazing.A hot cake absorbs syrup much better than a cold cake. Soak it while it's still warm! The cake is very fragile at this point. Be careful not to damage it. You may feel hesitant to use all the syrup, but please do! It makes the cake much more citrusy and moist.

Apply lemon glaze: Mix powdered sugar and lemon juice until smooth. Pour it over the cooled cake and spread it evenly. Decorate with diced pistachios or any topping while the icing is wet. Optional: Bake at 325ºF (163ºC) for just 1 minute. This sets the icing quickly and gives it a nice, crispy texture.