Preparation

• 1 FOR PUFF PASTRY: Bring water and butter to boil in heavy large saucepan over medium heat.
• 2 Add flour and salt all at once and stir until mixture pulls away from sides forming mass, about 2 minutes.
• 3 Transfer mixture to heavy duty mixer fitted with wire beater. Cool 5 minutes. With mixer running at medium speed, beat in eggs, one at a time, beating well after each addition. Beat until smooth. Cover loosely with plastic and let stand until cooled completely, about 2 hours.
• 4 Preheat oven to 425ºF and brush several heavy large baking sheets with butter.
• 5 Spoon half of dough into large pastry bag fitted with plain 1/2-inch round tip. Pipe 3/4 to 1-inch mounds onto baking sheets, spacing apart. Press peaks down onto mounds using moistened fingertip. Bake until golden and puffed, about 20 minutes.
• 6 Turn off oven. Pierce side of each puff with small sharp knife to allow steam to escape. Return puff to oven for 10 minutes to dry interior. Repeat with remaining pastry. (Puffs can be prepared ahead. Store in ziplock freezer bags at room temperature up to 2 days or freeze up to 2 weeks. If frozen, thaw carefully in single layer on paper towel lined baking sheets to avoid any moist spots.)
• 7 FOR PASTRY CREAM: Bring cream, milk and vanilla bean to boil in heavy large saucepan.
• 8 Whisk egg yolks, sugar, flour and salt to blend in large bowl. Gradually beat in hot cream mixture. Return mixture to saucepan and whisk over medium heat until mixture becomes very thick and boils. Transfer to bowl and remove vanilla bean. Cool completely, stirring occasionally. Cover with plastic and refrigerate until well chilled. (Can be made up to 4 days ahead.)
• 9 Spoon some of pastry cream into pastry bag fitted with plain 1/4-inch tip. Insert tip into score on each puff and fill with cream. Repeat until all puffs are filled.
• 10 FOR CARAMELIZED SUGAR AND ASSEMBLY: Butter inside of croquembouche mold.
• 11 Combine 1 cup sugar, 1/4 cup corn syrup and 1/4 cup water in heavy medium saucepan. Boil without stirring until mixture turns amber in color, brushing down any crystals that form on sides of pan with moist pastry brush, about 8 minutes. Remove from heat and place on cold surface to stop cooking.
• 12 Using tongs, carefully dip cream puff into caramel and place in mold. Repeat dipping and placing puffs into mold, fitting puffs evenly onto sides of mold, forming concentric circles until caramel is used. If caramel begins to harden, reheat briefly over medium heat to liquefy.
• 13 Repeat process for caramel as necessary. When sides are evenly coated with puffs, fill center with remaining puffs, dipping with caramel. Let stand until caramel is set in mold, about 10 minutes. Briefly heat sides of mold by holding for a few seconds over gas flame. Invert mold onto platter. Tap sides of mold several times with wooden spoon. Remove mold from Croquembouche.
• 14 FOR SPUN SUGAR: Combine 1 cup sugar, 1/4 cup corn syrup and 1/4 cup water in heavy medium saucepan. Boil without stirring until mixture turns amber in color, brushing down any crystals that form on sides of pan with moist pastry brush, about 8 minutes.
• 15 Remove from heat and place on cold surface to stop cooking. Let stand until caramel begins to form a thread when whisk is dipped into sugar and lifted into air, about 5 minutes. Dip whisk into caramel and raise high above Croquembouche. Wave whisk with sugar thread over and around croquembouche forming decorative threads. Repeat forming threads around Croquembouche by dipping whisk into caramel. Rewarm caramel as necessary if becomes too firm.
• 16 Croquembouche will hold up several hours at room temperature. Serve by cracking caramel with back of sharp knife and removing individual cream puffs.