Preheat oven to 325°. Grease and lightly flour bottom of tube pan.
Sift together flour, baking powder, and salt into a medium bowl. Set aside,
4 cups all-purpose flour, 1 teaspoon baking powder, ½ teaspoon salt
In the bowl of your electric mixer, cream the butter until light and fluffy. Gradually add sugar, beating until smooth. Add the eggs, one at a time. Mix just until the yolk is incorporated. Stop the mixer and scrape the sides and bottom. Turn the mixer back on low.
Add the dry ingredients (your flour, baking powder, and salt). Add lemon juice and vanilla. Don't overbeat the batter once you've added the flour. Stop the mixer and scrape the bottom and sides of the bowl to make sure everything is incorporated into the batter. Spoon the batter into the prepared pan.
¼ cup fresh lemon juice, 1 tablespoon pure vanilla extract
Bake for 1 hour and 25 minutes at 325℉, or until done. Remove from the oven and cool for 30 minutes, then invert the cake onto a wire rack to cool completely.