Preheat oven to 350 degrees F. Heavily grease then flour a bundt pan. Set aside.
In the bowl of a stand mixture, cream the butter. Add the sugar and beat until light and fluffy, 1 to 2 minutes.
Add eggs, incorporating after each addition, until well combined. Add flour and mix until just incorporated.
Add 7Up and lemon zest and turn on low. Slowly incorporate until the batter just comes together. Pour into the prepared bundt ban and smooth out the top.
Bake for an hour to 1 hour and 10 minutes. Remove from oven and place on wire cooling rack for 10 minutes. Invert bundt pan and allow to fully cool. Slice into 12 to 16 pieces and serve.