Into a blender add the Egg (1), Dry Mustard (1/2 teaspoon), Salt (1/4 teaspoon), Granulated Sugar (1/2 teaspoon), Lemon Juice (3 tablespoon), Cayenne Pepper (1 dash) and 1/3 cup of the Vegetable Oil (1/3 cup).
On medium high speed add the remaining 2/3 cup of Vegetable Oil (2/3 cup) in a slow drizzle through the top opening of the blender until thick and creamy. Set this "real mayonnaise" mixture aside.
Grease and flour your cake pan. For extra security, cut a round of parchment paper to fit the bottom of the pan and spray the parchment with vegetable spray. Set aside.
Combine the All-Purpose Flour (2 cup), Baking Soda (1 teaspoon), Granulated Sugar (1 1/2 cup), Salt (1/4 teaspoon) and Unsweetened Cocoa Powder (6 tablespoon).
Add 1 cup of the "real mayonnaise" you just made, Water (1 cup) and Mint Extract (1 teaspoon). Beat on medium speed with a hand mixer for 1-2 minutes, until well combined.
Pour the batter into the prepared cake pan and secure with the cake pan lid or tent loosely with tin foil vented with small slits. Place the crock pot lid on the crock pot and "bake" for 2 1/2-3 1/2 hours until cake tester comes out clean.
Cool to room temperature on a cake rack, then turn cake out onto a plate to frost.
In a large bowl, combine the Cream Cheese (8 ounce) and Unsalted Butter (1 cup). Mix on medium high speed with a hand mixer until well combined.
Add the Peppermint Extract (1 teaspoon), Vanilla Extract (1/2 teaspoon) and Powdered Confectioners Sugar (4 cup), 1 cup at a time beating till smooth.
Use a long serrated knife to slice the cake in half making two equal rounds.
Add a few tablespoons of icing to the bottom round and using an offset spatula, spread it evenly over the cake. Place the other half of the cake on top of the first tier. Set aside.
Divide the remaining frosting equally into 3 small bowls. Set aside one bowl of frosting with no food coloring added. Add 1 drop of Red Food Coloring (1 dash) to the second bowl. Add three drops of food coloring to the third bowl. Mix each bowl well so that you have gradually darkening colors
Start with the white frosting; put several spoonfuls on top of the cake and use your offset spatula to evenly cover only the top surface. Transfer the rest of the white frosting to a pastry bag fitted with a large round tip.
Pipe the white frosting over the top third of the sides of the cake. When you've used all of the white frosting, add the lighter pink frosting to the bag and pipe it around the next third of the cake. Then add the dark pink frosting and pipe it around the lower third of the cake.
Use your offset spatula to create the ombre effect. Hold the spatula vertically from top to bottom firmly against the cake and gently turn the cake plate around. This will smush the icing flat against the cake and the different tones will naturally run into each other.
Switch the round tip to a star tip and pipe any remaining frosting around the base of the cake. Sprinkle Hard Peppermint Candy (to taste) around the rim.