Blake Lively's Secret Weapon? Cupcakes

By Melody Chiu

06/09/2011 at 03:00 PM EDT

Superman has kryptonite. The Green Lantern has baked goods.

To make sure Ryan Reynolds didn't steal the spotlight, costar Blake Lively hit him with his ultimate weakness: cupcakes.

"It was just a way to sabotage Ryan," Lively, 23, said jokingly at a Los Angeles press conference for The Green Lantern, which opens June 17. "He was working out as much as he was, and I’m the girl. I’m supposed to look better."

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The Gossip Girl actress, who brushed up on her cooking skills at Le Cordon Bleu in Paris a few months ago, said she loves "to cook everything and anything."

"The most cooking I did was on this film," she said. "New Orleans was a great place to cook and eat."

Reynolds was happy to snatch up Lively’s sweet treats.

"[For] most actors, it’s coke and guns," he wisecracked. "For me, it’s baked goods."