By Hilary Russ

NEW YORK (Reuters) - McDonald's is toasting buns and melting cheese to improve the quality of its Big Mac and other burgers as it looks to boost sales.

Big Macs are also getting more sauce, and white onions are topping patties while they're still hot on the grill, according to a company statement on Monday.

We saw the opportunity to make a few changes in our kitchens to make them even more delicious, Tariq Hassan, McDonald's USA Chief Marketing and Customer Experience Officer, said in a statement.

To promote the new burgers, McDonald's is bringing back its Hamburglar character, which was originally used in the 1970s and '80s but was retired in the early 2000s except for a 2015 appearance to promote a limited-time sirloin burger, according to media reports.

Earlier this month, McDonald's began laying off hundreds of corporate U.S. employees amid a broader restructuring.

Even so, visits to the chain have been rising as it pushes meal deals with celebrities. Wall Street analysts expect comparable sales rise this quarter, with three brokerages lifting their price targets ahead of company earnings on April 25.

The burger changes have already been rolled out in Australia, Canada and Belgium. In the United States, they are available in some cities in California, Washington, Arizona and other Western states. They will be in effect nationwide by 2024, the company said.

(Reporting by Hilary Russ; Editing by Sandra Maler)