McDonald’s has said it’s been tweaking the menu. The changes are subtle, but McDonald’s said Monday they’ve resulted in the company’s “best burgers ever”, which include new buns, added Big Mac sauce to Big Macs, and caramelized onions to patties while they’re on the grill.

The changes are being applied to the preparation of the signature Big Mac, the McDouble, and the classic cheeseburgers and hamburgers.

These changes have already happened on the West Coast and are moving across the country.