Preheat oven to 350°F (175°C). Grease a 9x5-inch loaf pan and line with parchment. Cream butter and sugar on medium-high until pale and fluffy, about 3 minutes.

Beat in eggs one at a time, then mix in lemon zest, lemon juice, and vanilla.

Whisk flour, baking powder, baking soda, and salt. Add dry ingredients to wet in three additions, alternating with sour cream, starting and ending with dry. Stir just until combined.

Pour batter into the pan and smooth the top. Bake 55 to 65 minutes until a toothpick inserted in the center comes out clean. Cool in pan 10 minutes, then turn out onto a rack and cool completely.

Whisk powdered sugar with enough lemon juice to make a thick but pourable glaze. Drizzle over the cooled cake and let set 15 minutes before slicing.