Crepe truffle cake "Rose"

Ingredients

• 2 eggs
• 80 grams (2.8 ounces) sugar
• 5 grams (0.18 ounces) vanilla sugar
• 200 grams (7.05 ounces) flour
• 35 grams (1.23 ounces) alkalized cocoa
• 7 grams (0.25 ounces) cornstarch
• 3 grams (0.11 ounces) baking powder
• pinch of salt
• 40 grams (1.41 ounces) melted butter
• 360 grams (12.68 ounces / 1.5 cups) milk
• 100 grams (3.53 ounces / 0.42 cups) boiling water
• 250 grams (8.82 ounces) bitter chocolate
• 350 grams (12.35 ounces / 1.48 cups) whipping cream
• 100 grams (3.53 ounces / 0.83 cups) powdered sugar
• 50 grams (1.76 ounces) butter