Chocolate Éclairs

Ingredients

• 1 c (240 ml) water
• ½ c (113 g) unsalted butter, cut into ½-in pieces
• 1 Tbsp (12 g) granulated sugar
• ¼ tsp (1 g) salt
• 1 c (125 g) all-purpose flour
• 5 large (250 g) eggs
• 6 large (112 g) egg yolks
• ½ c (100 g) granulated sugar
• 3 Tbsp (24 g) all-purpose flour
• 3 Tbsp (24 g) cornstarch
• 2½ c (600 ml) whole milk
• Seeds from 1 vanilla bean pod
• ½ c (120 ml) heavy cream
• 4 oz (115 g) bittersweet chocolate, chopped
• 4 Tbsp (56 g) unsalted butter
• 1 Tbsp (21 g) corn syrup