Preheat oven to 320 degrees F.
With an electric mixer, cream butter. Add sugars and beat until fluffy and light. Add eggs, one at a time, mixing well after each.
In a separate mixing bowl, combine flour, baking powder, and salt.
Add dry ingredients to wet ingredients in mixing bowl, alternating with milk. Add in vanilla extract and beat until all ingredients are combined (but not longer).
Stir in chopped pecans.
Fill 2 round cake layers (I used 8”) with batter and bake for 60-75 minutes or until toothpick inserted comes out clean (the length could vary depending upon size of pan used).
For the filling: Mix cornstarch and brown sugar in medium saucepan. Set aside.
Beat together egg yolks, water and pinch of salt. Place saucepan on medium and add egg mixture to pan. Stir together on medium.
Add pecans. Stir consistently until mixture thickens.
Let boil for 1 minute, stirring the whole time.
Remove from heat, stir in butter, vanilla, and cinnamon.
Brush corn syrup on the top of cake layers and top with your filling.