Preheat the oven to 350°F (175°C). Grease and flour a 9×5-inch loaf pan or line it with parchment paper.

In a medium bowl, whisk together the flour, baking powder, and salt. Set aside.

In a large bowl, cream the butter and sugar together until light and fluffy.

Beat in the eggs one at a time, then mix in the sour cream, milk, lemon zest, lemon juice, and vanilla until smooth.

Gradually add the dry ingredients to the wet ingredients, mixing just until combined. Do not overmix.

Pour the batter into the prepared loaf pan and smooth the top.

Bake for 50–60 minutes, or until a toothpick inserted in the center comes out clean.

Let the cake cool in the pan for 10 minutes, then transfer to a wire rack to cool completely.

In a small bowl, whisk together the powdered sugar and lemon juice until smooth. Drizzle over the cooled loaf.

Allow the glaze to set before slicing and serving.