Preheat oven to 325°F (165°C). Grease and flour a Bundt pan or two loaf pans.

Cream the butter, shortening, and cream cheese together on medium speed until very light and fluffy, about 3–5 minutes.

Gradually add the granulated sugar, beating until the mixture is pale and increased in volume.

Add the eggs one at a time, mixing on low just until incorporated after each addition.

Mix in the vanilla extract and the salt (if using).

Add the cake flour in three additions, mixing on low only until no dry spots remain; do not overmix.

Scrape the batter into the prepared pan(s) and smooth the top.

Bake for 75–90 minutes, or until a toothpick inserted into the center comes out clean and the top is golden.

Cool in the pan for 15 minutes, then turn out onto a wire rack and cool completely before slicing.