Cédric Grolet has been a celebrated pastry chef for a decade. But only in the past two years or so has he thrown himself into highly orchestrated social-media performances.

Grab yourself some stiff frosting, like a dense Swiss buttercream, squeeze it into a bag with no air bubbles, select your tip ...

The South African chef got her start early ... Prince William and Harry loved when they were young. "They loved a piping bag full of meringue," said Robb. Robb was at Kensington Palace in 1997 ...

Owner and pastry chef Chelsey Erickson, 27, teaches the class with expertise and wit. When the batter is ready, she shows how to fill and handle a pastry bag to pipe small circles onto baking ...

Unfold the piping bag and twist the bag to gently tighten; use scissors to cut the tip off the bag. Pipe 1-inch rounds of chocolate on the parchment-lined baking sheet; tap pan on the counter to ...