Preheat your oven to 350°F (175°C). Grease and flour a 10-inch bundt pan or two 9-inch loaf pans.

In a large mixing bowl, combine the white sugar, unsalted butter, and shortening. Cream on medium speed for about 3-5 minutes until light and fluffy.

Add the large eggs one at a time, followed by the heavy cream, freshly squeezed Key lime juice, lime zest, and vanilla extract. Mix on low speed until just combined.

In a separate bowl, whisk together the cake flour, baking powder, and salt.

Gradually add the dry mixture to the wet ingredients, mixing on low speed until just combined.

Pour the batter into the prepared pan(s) and bake for 55-65 minutes or until a toothpick inserted comes out clean.

Allow the cake to cool in the pan for about 10 minutes before turning it out onto a wire rack.

Prepare the glaze by whisking together the powdered sugar, Key lime juice, and vanilla extract until smooth.

Drizzle the glaze over the cooled cake and allow it to set before slicing.