Preheat your oven to 350°F (175°C) to ensure even baking and proper rise.
Grease your 9x5 inch loaf pan with butter or non-stick spray, then lightly dust it with flour to help the cake release easily.
In a medium bowl, whisk together the all-purpose flour, baking powder, and salt until well combined. Set aside.
In a large mixing bowl, beat together the unsalted butter and Crisco shortening with a stand mixer or hand mixer on medium speed until light and fluffy, about 3-5 minutes.
Gradually add the sugar to the butter and shortening mixture, continuing to beat until well blended and fluffy.
Add the eggs one at a time, mixing well after each addition to achieve a light texture.
Pour in the whole milk and lemon juice, mixing until everything is well combined, enhancing the flavor with acidity.
Gradually add the dry ingredient mixture to the wet ingredients, mixing until just combined. Avoid overmixing to prevent a dense cake.
Fold in the lemon zest with a rubber spatula, distributing it evenly throughout the batter for an extra citrus burst.
Pour the batter into the prepared loaf pan and smooth the top with a spatula. Bake for 60-70 minutes or until a toothpick inserted in the center comes out clean.
Remove the cake from the oven and let it cool in the pan for about 10 minutes, then transfer to a cooling rack to cool completely.