PREPARE OVEN & CAKE PANS: Preheat oven to 350 degrees Fahrenheit. Put parchment rounds on the bottom of two 9″ cake pans. Spray with non-stick spray.
MAKE BUTTERMILK: Put 2 tablespoons of white vinegar in a 1-cup measuring cup. Fill the remainder with whole milk. Let sit for 5 minutes. Stir before adding to the cake.
MIX CAKE: Mix all cake ingredients except the amaretto for about 2 minutes until light and fluffy. Pour into prepared cake pans. Bake for 25 minutes. When a toothpick comes out clean, the cake is done.
POKE HOLES IN CAKES: Let cool for 20 minutes. Remove the cakes from the pans and put each layer upside down on a flat plate. Poke holes in the bottom of the cake using handle of a wooden spoon.
ADD ALCOHOL: Spritz or drizzle about 2 tablespoons of amaretto liqueur on the still-warm cake.
CREAM FILLING: Combine the sugar and corn starch in a medium saucepan over medium heat. Slowly add the milk. Bring to a boil and boil for 1 minute.
TEMPER THE EGG YOLKS: In a separate medium-sized bowl, whisk the egg yolks. Add a small amount of the hot cream to the egg mixture beating constantly. Slowly add more of the cream to the egg mixture while continuing to whisk. Add at least 1/3 of the cream mixture to the egg mixture before adding it back into the saucepan. Boil for 1 more minute.
FINISH CREAM FILLING: Remove the pudding from heat and whisk in butter, vanilla and salt. Whisk constantly for several minutes as the pudding cools to keep a skin from forming.
ADD CREAM TO CAKE: When the cream is starting to cool, slowly pour 1/2 of the pudding over each layer. If the pudding starts to go over the side of the cake, allow the pudding to set and then spoon the remaining pudding into the center of the cake and smooth outward.
GANACHE: Rinse the saucepan with hot water and return to medium heat. Add the cream. Stir occasionally until bubbles form at the edges of the pan. Remove from heat and pour over chocolate chips. Let stand for 5 minutes and then whisk until smooth. Add amaretto liqueur and toffee extract.
Allow to set in refrigerator over night. Slice immediately before serving. Serve chilled.