Preheat the oven to 325ºF, and butter and flour a 9-inch round cake pan.
Cream the butter and sugar for 5 minutes. Scraped down the sides. Then, whisk in the eggs on high for 5 minutes.
Fold in the sour cream, food coloring (optional), lime juice, zest, and ginger.
Sift together the flour, baking soda, and salt. Then gently incorporate
Pour batter into prepared pan, and bake for 30-40 minutes until a toothpick inserted in the center comes out clean.
Allow to cool in the pan until the pan is safe to touch. Then turn the cake out onto a wire rack to finish cooling completely.
Coconut Cream Frosting
Melt the coconut cream and oil together for about 30 seconds in the microwave, and whisk to thoroughly combine. Transfer to a small bowl and refrigerate to solidify but not chill for roughly 1 hour.
In the bowl of your stand mixer, fitted with the whisk attachment, whip one egg white to soft peaks. Remove from the bowl to set aside.
Whip the coconut cream and oil mixture until fluffy. Then, add in the meringue. Slowly sprinkle in the powdered sugar to form the frosting and finish with the lime and ginger.
Frost the cake with an offset spatula.
Optionally, you can decorate with sugared lime slices, lime zest, and candied ginger.
Notes
*Coconut Cream Notes: Get a can of full fat coconut milk. Place this in the refrigerator overnight. The cream of the coconut milk will solidify at the top for easier scooping. Avoid using the coconut water found at the bottom of the can as it will make your frosting too loose.