In a medium sauce pan, bring milk to a rolling boil.
In another large sauce pan, add sugar, flour and salt. Slowly whisk in the boiled milk over medium heat. Continue whisking until milk mixture has thickened, 5-6 minutes.
Whisk a small amount of the thicken milk mixture to the beaten egg yolks until well combined.
Stir eggs into remaining milk mixture and whisk for 1 minute longer.
Remove from heat and stir in butter, vanilla and liquor and set aside.
Bring a large pot of water to a boil. Add perogies and cook stirring occasionally for 6 mins.
Drain perogies and divide in dessert bowls. Top with bananas, custard and drizzle with cookie crumble.