Preheat the oven to 350 degrees. Place sugar, butter, eggs and lemon extract in the bowl of an electric mixer, then beat on medium speed until fluffy, about 2 minutes. Add the flour and 7UP in three batches: Add 1 cup flour and 1/3 cup of 7UP, then beat at medium speed until flour is incorporated, about 30 seconds. Scrape down the sides of the bowl. Repeat with remaining flour and 7UP. Lightly coat a 12-cup Bundt pan with nonstick cooking spray, then pour the batter into the pan. Tap and shake the pan gently to level the batter, then bake until golden brown, about 1 hour. Let cool 5 minutes in pan, then invert the Bundt pan onto a serving plate. Let cool to room temperature. Slice and serve plain, or top with ice cream. 7UP pound cake also pairs nicely with strawberries and whipped cream.