Heat oven to 315 degrees F. Spray a 10-cup bundt pan with nonstick baking spray. In the bowl of a stand mixer fitted with the whisk attachment, beat the butter for 2 minutes on high speed. Slowly add the sugar and salt. Cream together for an additional 7 minutes until very pale yellow and fluffy. Add the eggs one at a time, combining well after each addition and scraping down the sides of the bowl as needed.
Turn your mixer down to the lowest speed setting and slowly add the flour in two batches. Do not overbeat. Pour in the 7UP and lemon extract. Scrape down the sides and bottom of your mixing bowl and mix the batter until just combined. Again, be careful not to overmix.
Pour the batter into the prepared pan and bake for 75 to 85 minutes, or until a toothpick inserted into the center of the cake comes out clean.
Let the cake cool in the pan for at least 10 minutes before inverting onto a serving plate. Let cool to room temperature.