Preheat oven to 325 degrees F (165 degrees C).

Grease and flour a 9-inch fluted tube pan (such as a Bundt(R)).

In a bowl, mix flour, baking powder, and salt together.

Sift the flour mixture twice into a separate bowl.

In another large bowl, cream butter, shortening, and sugar until smooth.

Stir eggs and milk into creamed mixture until thoroughly combined.

Gradually mix flour into moist ingredients to make a smooth batter.

Stir lemon and vanilla extracts into batter.

Continue mixing until no sugar granules are visible.

Pour batter into prepared tube pan.

Bake in the preheated oven until top is springy and cake is set in the center, about 90 minutes.

Let cake cool in the pan until sides separate from pan.

Turn out onto a rack to finish cooling.