Preheat your oven to 325°F (165°C). Grease and flour a 9x5-inch loaf pan, or line it with parchment paper for easy removal.
In a medium bowl, whisk together 1 and 1/2 cups of all-purpose flour, 1/2 teaspoon of baking powder, and 1/4 teaspoon of salt. Set aside.
In a large mixing bowl, cream together 1 cup of unsalted butter (at room temperature) and 1 cup of granulated sugar until light and fluffy.
Beat in 4 large eggs, one at a time, until well combined. Then, mix in the zest of 2 lemons for a vibrant lemon flavor.
Gradually add the dry ingredients to the wet ingredients, mixing until just combined. Be careful not to overmix, as this can result in a dense cake.
Mix in 2 tablespoons of freshly squeezed lemon juice to enhance the lemon flavor. Stir until evenly distributed throughout the batter.
Pour the batter into the prepared loaf pan, spreading it evenly with a spatula.
Place the loaf pan in the preheated oven and bake for 50-60 minutes, or until a toothpick inserted into the center comes out clean. The top should be golden brown and the edges slightly pulling away from the sides of the pan.