Napoleon Cake — step-by-step recipe with photos

Ingredients

• 250 ml milk
• 200 g sugar
• 100 g butter
• 1 egg
• 1 tsp salt (level)
• 1 packet vanilla sugar (10 g)
• 2 tbsp cognac (or vodka, or 6% natural vinegar, or 1 tbsp 9% white vinegar)
• 600–650 g flour
• 1 liter milk
• 200 ml heavy cream (any fat content; I used 20%)
• 250 g sugar
• 60 g flour
• 4 egg yolks