1 cup water
1 cup flour
1 Tsp. baking Powder
1/4 tsp. salt
1/2 cup butter
4 cups milk
1 cup sugar
5 egg yolks
2 Tsp. vanilla
5 Tbsp. cornstarch + 5 Tbsp. flour
1 cup butter at room temperature
Bring 1 cup water and butter to boil. Add flour, BPowder and salt stiring quickly on low heat. Remove from pan and mix 1 minute until dough easily comes off walls of pot.
Set aside and cool. Transfer to a mixing bowl with whisk and one by one add one egg until smooth like butter. Grease two 9 by 13 pans and lightly dust with flour. Patiently spread 1/2 mixture into each pan until base of pan is covered.
Pop into a preheated oven at 400 degrees for 25 minures. I used the top rack in my oven.
It comes out looking like the mountains.
While crust cooks, in a bowl whisk together 1 cup milk, vanilla, yolks and cornstarch and flour until smooth.
In a saucepan put the remaining 3 cups milk on medium until sides of milk get tiny bubbles..do not boil. Add the sugar stirring quickly until well combined and melted. Slowly add the flour-egg mixture whisking consistently on low-medium heat until everything starts to thicken like a pudding. Remove from heat and pour into a bowl and cover with saran so it doesn't form a layer of skin on top of filling. Let cool. In a mixing bowl mix 1 cup butter and slowly add cooled custard to butter until well combined.
Remove one crust from pan and set on a wire rack.
Line the empty pan with overlapping parchment paper. Set crust back in pan. This is for easy removal later. Spoon filling over crust in pan and cover with remaing crust pressing down gently. I actually had to slice a bit of my high mountain top off before it spooned on the fillling. Cool in fridge for 2 hours.