Adjust your oven rack to the middle position and preheat the oven to 325°F. Prepare your 12-cup Bundt pan by spraying liberally with nonstick baking spray.
In the bowl of your stand mixer fitted with the whisk attachment, add butter and sugar and beat on high for 8 minutes until pale yellow and fluffy.
Meanwhile, whisk together the cake flour and salt in a medium bowl and set aside.
Once the butter and sugar mixture is pale and fluffy, reduce the mixer speed to medium, and add eggs one at a time, combining well after each addition and scraping the sides and bottom as needed.
Reduce the mixer speed to low and slowly add the flour and salt mixture in two increments and beat until just combined. Do not overmix.
Place half of the batter in a large bowl and gently fold the orange zest, juice, extract, and food coloring (if using) into the batter until evenly mixed. In the bowl of the mixer with the remaining half of the batter, gently fold in the vanilla extract and heavy cream.
Pour the vanilla batter into the bowl with the orange batter and gently swirl together with a skewer or knife. Then pour into the prepared pan and smooth until even. Finally, swirl once more to create a distinct swirl pattern. (Be careful not to overmix the batters, as the entire cake will be orange.)
Place in the oven and bake until a toothpick inserted in the center of the cake comes out mostly clean, about 1 hour and 10 minutes.
Remove the cake from the oven and cool in the pan for 15 minutes. Then invert onto a wire rack to cool fully, about 1 hour.