Preheat your oven to 350°F (175°C). Grease and line a 9x5-inch loaf pan with parchment paper.

Whisk together the flour, baking powder, baking soda, and salt in a medium bowl until mixed. Set aside.

Beat the softened butter and granulated sugar together in a large bowl until light and fluffy, about 2–3 minutes.

Mix in the eggs, vanilla extract, lemon zest, and fresh lemon juice to the butter mixture until well blended.

Gradually incorporate the dry ingredients into the wet mix, alternating with the buttermilk; stir gently until just combined.

Pour the batter into the prepared loaf pan and smooth the top with a spatula.

Bake for 50–60 minutes, or until a toothpick inserted comes out clean. Cover with aluminum foil if browning too quickly.

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

Whisk together the powdered sugar and lemon juice in a small bowl until smooth; adjust consistency for drizzling.

Drizzle the glaze over the cooled cake, letting it cascade down the sides.

Slice the cake into pieces and serve.