NEW YORK — Competition among casual restaurant operators heated up yesterday as Denny's Corp. launched free Grand Slam breakfasts in an effort to reacquaint customers with its brand and showcase its meals as value-friendly options for cash-conscious consumers.

The restaurant chain was giving away the free Grand Slams, which include pancakes, eggs, bacon strips and sausage links, to any customer visiting its restaurants yesterday between 6 a.m. and 2 p.m.

The promotion was a hit at Denny's locations in Hawai'i. Customer traffic at the chain's four restaurants on O'ahu was about triple the volume of an average Tuesday, said Rick Holloway, area manager.

"We had a fairly steady turnout for most of the eight-hour promotion. We were ready for them. We had some guests seated at their table and waiting for coffee at 6 a.m. At 2 p.m. we gave rain checks to anyone who was still standing in line," he said.

Denny's has promoted the freebie heavily, with a 30-second ad that aired during the third quarter of the Super Bowl on Sunday, another 15-second ad during the post-game show and a full-page ad in USA Today's Monday editions. The company reported 14 million hits on its Web site between Sunday night and Monday morning — the site read "service unavailable" at midday yesterday. By late afternoon, when the site was back up, Denny's had recorded 40 million hits since Sunday night.

Nationwide, the Spartanburg, S.C.-based company said it served up 2 million free Grand Slams, said spokeswoman Cori Rice.