Preheat oven to 325 °F. Butter and flour a bundt pan.
Whisk together flour, baking powder, baking soda, and salt in a medium-sized bowl. Set aside.
Place butter, sugar, and lemon zest in the bowl of a stand mixer. Using a paddle attachment, mix at medium-high speed until creamy, about 3 minutes. Scrape the bowl.
Add the eggs, one at a time, mixing for one minute after each addition. Scrape the bowl.
Add the sour cream and mix on low until combined.
Add flour and mix on low until just combined.
Pour the batter into the bundt pan. Place in oven and bake for 65 minutes, or until a toothpick inserted in the center of cake comes out clean.
While the cake is baking, make the simple syrup: combine lemon juice and sugar in a small saucepan. Heat and stir until the mixture comes to a simmer. Simmer for five minutes, making sure the sugar has dissolved.
When the cake is done, remove the cake from the oven and brush it with half the simple syrup mixture. Allow the cake to cool for ten minutes, then turn the cake out of the pan. Brush the top with the remaining syrup.
Allow the cake to cool completely and dust with powdered sugar or coat with a glaze (whisk 1 cup of sifted powdered sugar with two tablespoons of lemon juice).
