Heat oven to 375 degrees. In a medium bowl, whisk starch, gum, salt, baking powder, pudding; set aside. In a small bowl, beat yolk, cream, and vanilla with fork until combined; set aside.
In standing mixer, cream butter and sugar at medium-high speed until light and fluffy, 3 to 4 minutes. Scrape down bowl with rubber spatula. With mixer running at medium speed, add yolk/cream mixture and beat until incorporated, about 30 seconds. Scrape down bowl. With mixer running at low speed, add starch mixture until the dough is formed, about 1 to 2 minutes. ( If too dry add an extra tablespoon of heavy cream. )
In a well greased 9 x 13 pan, press the dough into an even layer. Bake until light golden brown, about 20 to 25 minutes. Place the base in the fridge for 15 minutes to cool.
Evenly sprinkle remaining ingredients one by one over the base to form layers, beginning with the chocolate, followed by the butterscotch chips (or those delicious salted caramel chips from Trader Joes) and the sweetened coconut (can use unsweetened - just adjust the phe). Pour the condensed coconut milk evenly over the top -- spread with a rubber spatula to make sure it's evenly distributed.
Bake 25 to 30 minutes until edges are golden brown and the middle is set. Allow to cool completely. Cut into 1 inch squares.
