01 - Preheat oven to 350°F. Thoroughly grease and flour a 10-cup Bundt pan.
02 - In a large bowl, beat butter and granulated sugar with an electric mixer until light and fluffy, about 3 to 4 minutes.
03 - Beat in eggs one at a time, mixing well after each addition.
04 - Mix in lemon zest, lemon juice, and vanilla extract until evenly combined.
05 - In a separate bowl, whisk together flour, baking powder, baking soda, and salt.
06 - Add dry ingredients to wet mixture in three parts, alternating with sour cream; begin and end with dry ingredients. Mix until just combined, avoiding overmixing.
07 - Spoon batter evenly into prepared pan and smooth the surface.
08 - Bake for 45 to 55 minutes, or until a toothpick inserted into the center comes out clean.
09 - Meanwhile, combine lemon juice and sugar in a small saucepan over medium heat. Stir until sugar dissolves, then remove from heat.
10 - Let cake cool in pan for 15 minutes. Carefully invert onto wire rack set over a tray.
11 - Brush lemon syrup evenly over warm cake and allow it to soak in. Cool completely.
12 - Whisk powdered sugar with lemon juice until smooth and pourable. Drizzle over cooled cake.
13 - Allow glaze to set for at least 15 minutes before slicing and serving.