1. Prepare a 9-inch springform pan by lining the sides with parchment paper that sticks about an inch above the sides of the pan.
2. To make the mousse, beat cream cheese and sugar for together in a large mixer bowl until smooth.
3. Add 2 tablespoons of milk and the vanilla extract to the cream cheese mixture and beat until smooth. Set the cream cheese mixture aside and make the whipped cream.
4. Add the heavy whipping cream and powdered sugar to a large mixer bowl fitted with the whisk attachment and whip on high until stiff peaks form.
5. Carefully fold whipped cream into cream cheese mixture.
6. Divide the cream cheese mixture evenly between 3 bowls. Leave one bowl as is (white), then color one yellow and the other orange. I like to use gel icing color – you don’t have to use as much to get a strong color and it won’t thin out the mixture.
7. Place the remaining 1/2 cup of milk in a small bowl. Place a single layer of shortbread cookies into the bottom of the pan, dipping each into the milk before adding.
8. Top the cookies with the yellow filling and spread into an even layer.
9. Place another layer of shortbread cookies on top of the yellow layer, dipping them in the milk first.
10. Top the cookies with the orange filling and spread into an even layer.
11. Place another layer of shortbread cookies on top of the orange layer, dipping them in the milk first
12. Spread the final layer of white filling evenly on top of the cookies.
13. Refrigerate cake until firm, 4-5 hours or overnight.
14. Once firm, remove the springform pan sides from the cake and set on a serving plate.
15. Make the whipped cream topping. Add the heavy whipping cream, powdered sugar and vanilla extract to a large mixer bowl fitted with the whisk attachment and whip on high until stiff peaks form.
16. Pipe swirls of whipped cream around the edge of the cake and top it with some candy corn. Refrigerate until ready to serve.