1 cup lemon-lime carbonated beverage (such as 7Up®)
1 cup sifted confectioners' sugar
1/4 cup milk
1/2 teaspoon vanilla extract
Preheat oven to 325 degrees F (165 degrees C). Generously grease a fluted tube pan (such as Bundt(R)).
Beat white sugar and butter together in a bowl using an electric mixer until creamy and smooth; add eggs, 1 at a time, mixing well after each addition. Stir flour, 1 cup at a time, blending well after each addition until batter is smooth; stir in lemon extract. Mix lemon-lime beverage into batter and pour into the prepared pan.
Bake in the preheated oven until a toothpick inserted in the center of the cake comes out clean, about 1 hour 15 minutes. Remove cake from pan immediately.
Beat confectioners' sugar, milk, and vanilla extract together in a bowl using an electric mixer on medium until glaze is smooth. Pour glaze over warm cake.