Preheat oven to 325 degrees. Generously spray a bundt pan with baking spray with flour, set aside.
In a medium size bowl, sift together flour and kosher salt.
In the bowl of a stand mixer fitted with the paddle attachment, add butter and beat for 2-3 minutes. Slowly add sugar to butter and mix until light and fluffy. About 6-7 minutes.
Add eggs, one at a time, and beat well after each addition.
Turn mixer to lowest speed and add flour to butter mixture in three additions. Mix each addition until just combined, scraping down the sides as necessary. Be careful not to overmix.
Lastly, add lemon juice, lemon zest, vanilla extract, and 7 UP. Mix until just combined, scraping down the sides as needed.
Pour batter into prepared bundt pan and bake for 1 hour to and 1 hour and 10 minutes or until a toothpick inserted into the center of the cake comes out clean.
Let cake cool in budnt pan on wire rack for 10 minutes. Invert and remove from pan. Let cake cool completely on a wire rack.