Boston Cream Pie | Williams Sonoma

Ingredients

• 2 1/2 cups all-purpose flour
• 3 1/2 tsp. baking powder
• 1/2 tsp. salt
• 6 Tbs. (3/4 stick) unsalted butter,<br>  at room temperature
• 1 2/3 cups sugar
• 1 cup milk
• 2 tsp. vanilla extract
• 3 eggs
• 9 egg yolks
• 1/2 cup sugar
• Large pinch of salt
• 4 Tbs. cornstarch
• 1 vanilla bean
• 2 1/2 cups milk
• 1/4 cup heavy cream
• 1 cup sugar
• 3/4 cup plus 1 Tbs. water
• 1/2 cup cocoa powder
• 1 1/2 tsp. powdered gelatin