Preheat your oven to 350°F (175°C).

Grease your loaf pan with butter or line it with parchment paper.

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

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

In a separate bowl, whisk together the flour and baking powder.

Gradually add the dry ingredients to the butter mixture, alternating with milk.

Fold in the lemon zest.

Pour the batter into the prepared loaf pan and bake for 45 minutes or until a toothpick comes out clean.

Let the cake cool slightly before glazing.