Preheat the oven to 350°F (175°C). Grease and flour a loaf pan.

In a mixing bowl, cream together the softened butter and granulated sugar until light and fluffy.

Add the eggs one at a time, mixing well after each addition.

In another bowl, combine the sifted flour, baking powder, and salt.

Gradually add the dry ingredients to the butter mixture, alternating with the buttermilk. Mix until just combined.

Stir in the lemon zest and vanilla extract.

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

Bake for 60-70 minutes, or until a toothpick inserted into the center comes out clean.

Allow the cake to 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 the glaze over the cooled cake before serving.