Preheat the oven to 300 degrees F (150 degrees C). Grease and flour a tube pan.

Beat butter, sugar, and shortening together with an electric mixer until creamy and fluffy. Add eggs, one at a time, beating well after each addition.

Sift flour and baking powder together in another bowl. Add to creamed mixture, alternating with milk and sour cream. Mix in vanilla extract and lemon extract. Pour into the prepared pan.

Bake in the preheated oven until a toothpick inserted into the center of the cake comes out clean, about 1 hour and 30 minutes.