Preheat your oven to 325°F (165°C) and line a 9x5-inch loaf pan with parchment paper, leaving a slight overhang on the edges for easy removal.

In a large mixing bowl, beat the softened butter and granulated sugar together using an electric mixer until pale, light, and fluffy, which should take about 3 to 4 minutes.

Add the room temperature eggs one at a time, beating well after each addition to prevent the mixture from curdling. If the batter starts to separate slightly, beat in a tablespoon of the measured flour.

In a separate medium bowl, whisk together the all-purpose flour, baking powder, and salt. Gently fold this dry mixture into the wet ingredients using a rubber spatula until just combined.

Stir in the fresh lemon zest, lemon juice, and whole milk until the batter is smooth and reaches a thick dropping consistency.

Pour the batter into the prepared loaf pan, smoothing the top flat with the back of a spoon. Bake in the preheated oven for 55 to 60 minutes, or until a wooden skewer inserted into the center comes out clean and the top is golden brown.

Remove the cake from the oven and allow it to cool in the pan for 15 minutes before transferring it to a wire rack to cool completely. Serve generous slices at room temperature alongside a warm cup of Earl Grey tea.