Offer these cream puffs as a surprise at the end of the evening, long after the wedding cake has been devoured.
Bring butter, sugar, salt, and the water to a boil in a medium saucepan over medium heat. Remove from heat, and quickly stir in flour. Return pan to medium-high heat; stir constantly until mixture pulls away from sides and a film forms on bottom of pan, about 3 minutes.
Transfer to mixer bowl; beat on low speed until slightly cooler, about 1 minute. Raise speed to medium, and beat in eggs one at a time. Beat until a soft peak forms when you touch batter with a finger. If peak does not form, lightly beat in remaining egg white.
Line 2 baking sheets with parchment paper. Trace 1 1/2-inch round cutter, trace inside of round circles on parchment, 2 inches apart; on prepared sheets, flip parchment over so writing won't touch food; then flip parchment. Place batter in a pastry bag fitted with a 1/2-inch plain tip (such as Ateco #806); pipe batter to fill circles. Smooth peaks with a moistened finger to ensure even rising. Freeze on baking sheets until firm, about 30 minutes.
Heat oven to 375 degrees. Bake puffs until are puffed and pale golden brown all over, 25 to 30 minutes. Cool completely in pans on wire racks. Store in an airtight container at room temperature up to overnight.
Shortly before serving, whisk pastry cream to soften. Beat heavy cream in mixer bowl on medium-high until stiff peaks form. In a separate bowl, working in 2 batches, fold whipped cream into pastry cream with a rubber spatula. Place in a pastry bag with a 1/8-inch plain tip (such as Ateco #800). Insert tip into bottom of each puff; squeeze bag to fill. Refrigerate in an airtight container. Serve within a few hours, topping each with a spun-sugar cloud.