Napoleon cake with vanilla custard & cherry jam

Ingredients

• 600 grams (4.2 cups) all-purpose flour
• 380 grams (1.7 cups) 82.5% butter
• 110 grams (2 large) eggs
• 300 grams (1.3 cups) 20% sour cream
• 0.3 teaspoons (1.8 grams) salt
• 70 grams (0.5 cups) flour for rolling
• 490 grams (3.4 cups) cherries
• 110 grams (0.44 cups) cherry juice (from the thawed berries)
• 100 grams (0.5 cups) sugar
• 11 grams (0.04 cups) apple pectin
• 400 grams (1.75 cups) coconut milk
• 450 grams (2 cups) 3.5% milk
• 100 grams (5 large) egg yolks
• 35 grams (0.28 cups) cornstarch
• 40 grams (0.34 cups) all-purpose flour
• 190 grams (0.95 cups) sugar
• 10 grams (0.042 cups) vanilla sugar
• 100 grams (3.52 ounces) zéphyr white chocolate
• 380 grams (1.7 cups) mascarpone
• 380 grams (1.7 cups) cream cheese
• 80 grams (0.35 cups) 82.5% butter
• 85 grams (0.68 cups) powdered sugar
• 80 grams (0.32 cups) cherry jam